diff --git a/webif/lib/queue.class b/webif/lib/queue.class
index b9811cf..59715a0 100644
--- a/webif/lib/queue.class
+++ b/webif/lib/queue.class
@@ -53,77 +53,127 @@ proc {queue dbhandle} {args} {
 		return $::queue::db
 	}
 
-	if {![file exists /mod/etc/queue.db]} {
-		set ::queue::db [sqlite3.open /mod/etc/queue.db]
-		$::queue::db query {
-			create table queue(
-				id integer primary key autoincrement,
-				file text,
-				action text,
-				args text,
-				start integer default 0,
-				status text default 'PENDING',
-				log text default '',
-				runtime integer,
-				retries integer default 0,
-				interrupts integer default 0,
-				submitted integer default 0,
-				last integer default 0
-			);
+	try {
+		set db [sqlite3.open /mod/etc/queue.db]
+	} on error {msg} {
+		stderr puts $msg
+		return 0
+	}
+	if {[catch {$db query { select count(*) from queue, config; }}]} {
+		catch {$db {drop table queue}}
+		catch {$db {drop table config}}
+		try {
+			$db query {
+				create table queue(
+				    id integer primary key autoincrement,
+				    file text,
+				    action text,
+				    args text,
+				    start integer default 0,
+				    status text default 'PENDING',
+				    log text default '',
+				    runtime integer,
+				    retries integer default 0,
+				    interrupts integer default 0,
+				    submitted integer default 0,
+				    last integer default 0
+				);
+			}
+			$db query {
+				create table config(
+				    var text,
+				    val text
+				);
+			}
+			$db query {
+				insert into config values('version', 3);
+			}
+			$db query {
+				create unique index file on queue(file, action);
+			}
+		} on error {msg opts} {
+			stderr puts $msg
+			catch {$db close}
+			return 0
 		}
-		$::queue::db query {
-			create table config(
-				var text,
-				val text
-			);
-		}
-		$::queue::db query {
-			insert into config values('version', 3);
-		}
-		$::queue::db query {
-			create unique index file on queue(file, action);
-		}
-	} else {
-		set ::queue::db [sqlite3.open /mod/etc/queue.db]
 	}
 
-	return $::queue::db
+	return [set ::queue::db $db]
+}
+
+proc {queue dbquery} {query args} {
+	set db [queue dbhandle]
+	try {
+		return [$db query $query {*}$args]
+	} on error {msg opts} {
+		return {}
+	}
+}
+
+proc {queue dbaction} {query args} {
+	set db [queue dbhandle]
+	try {
+		$db query $query {*}$args
+		return true
+	} on error {msg opts} {
+		return false
+	}
+}
+
+proc {queue dbqueryl} {query_list {txn_mode ""}} {
+	set db [queue dbhandle]
+	try {
+		if {$txn_mode ne ""} {
+			if {$txn_mode ni { immediate exclusive }} {
+				set txn_mode "deferred"
+			}
+			$db query "begin %s transaction" $txn_mode
+		}
+		foreach q $query_list {
+			$db query {*}$q
+		}
+		if {$txn_mode ne ""} {
+			$db query "commit transaction"
+		}
+		return true
+	} on error {msg opts} {
+	}
+	if {$txn_mode ne ""} {
+		catch { $db query "rollback transaction" }
+	}
+	return false
 }
 
 proc {queue startup} {{days 7}} {
 	if {$days == 0} { set days 7 }
-	set db [queue dbhandle]
-	$db query {
+	return [queue dbqueryl { { {
 		update queue
 		set status = 'INTERRUPTED',
 		log = 'Job will be retried automatically.',
 		retries = retries + 1,
 		interrupts = interrupts + 1
 		where status = 'RUNNING'
-	}
-	$db query {
+	} } { {
 		update queue
 		set status = 'FAILED',
 		log = 'Too many interrupts.'
 		where status = 'INTERRUPTED'
 		and interrupts >= 5
-	}
-	$db query {
+	} } { {
 		update queue
 		set status = 'PENDING'
 		where status = 'DEFER'
-	}
-	$db query {
+	} } { {
 		delete from queue
 		where status in ('COMPLETE', 'FAILED')
 		and submitted < %s
 	} [expr [clock seconds] - 86400 * $days]
+	} } ]
 }
 
 proc {queue fetch} {file action} {
-	set db [queue dbhandle]
 
-	foreach row [$db query {
+	foreach row [queue dbquery {
 		select * from queue
 		where file = '%s'
 		and action = '%s'
@@ -134,23 +184,23 @@ proc {queue fetch} {file action} {
 }
 
 proc {queue insert} {args file action} {
-	set db [queue dbhandle]
 
 	set status "PENDING"
 	if {"-hold" in $args} { set status "HOLD" }
 
 	set file [queue key $file]
 
-	$db query {
+	if {[queue dbaction {
 		insert or ignore into queue(submitted, file, action, status)
 		values(%s, '%s', '%s', '%s')
-	} [clock seconds] $file $action $status
+	} [clock seconds] $file $action $status]} {
 
-	return [queue fetch $file $action]
+		return [queue fetch $file $action]
+	}
+	return 0
 }
 
 proc {queue delete} {file {action "*"}} {
-	set db [queue dbhandle]
 
 	set q "
 		delete from queue
@@ -161,11 +211,10 @@ proc {queue delete} {file {action "*"}} {
 		append q " and action = '%s'"
 	}
 
-	$db query $q [queue key $file] $action
+	return [queue dbaction $q [queue key $file] $action]
 }
 
 proc {queue delete_by_id} {id} {
-	set db [queue dbhandle]
 
 	set q "
 		delete from queue
@@ -173,11 +222,10 @@ proc {queue delete_by_id} {id} {
 		and status != 'RUNNING'
 	"
 
-	$db query $q $id
+	return [queue dbaction $q $id]
 }
 
 proc {queue resubmit} {id} {
-	set db [queue dbhandle]
 
 	set q "
 		update queue
@@ -186,11 +234,10 @@ proc {queue resubmit} {id} {
 		and status in ('FAILED', 'HOLD', 'COMPLETE')
 	"
 
-	$db query $q $id
+	return [queue dbaction $q $id]
 }
 
 proc {queue hold} {id} {
-	set db [queue dbhandle]
 
 	set q "
 		update queue
@@ -199,15 +246,13 @@ proc {queue hold} {id} {
 		and status not in ('RUNNING', 'COMPLETE')
 	"
 
-	$db query $q $id
+	return [queue dbaction $q $id]
 }
 
 proc {queue status} {file} {
 	if {$file eq "0"} { return "" }
 
-	set db [queue dbhandle]
-
-	set ret [$db query {
+	set ret [queue dbquery {
 		select group_concat(action)
 		from queue
 		where file = '%s'
@@ -230,10 +275,9 @@ proc {queue check} {file {q "any"}} {
 }
 
 proc {queue all} {} {
-	set db [queue dbhandle]
 
 	set ret {}
-	foreach row [$db query {select * from queue order by id}] {
+	foreach row [queue dbquery {select * from queue order by id}] {
 		lappend ret [queue new $row]
 	}
 	return $ret
@@ -243,7 +287,7 @@ proc {queue pending} {} {
 	set db [queue dbhandle]
 
 	set ret {}
-	foreach row [$db query {
+	foreach row [queue dbquery {
 		select * from queue
 		where status in ('PENDING', 'INTERRUPTED')
 		and start < %s
@@ -259,23 +303,20 @@ proc {queue size} {} {
 }
 
 proc {queue version} {} {
-	set db [queue dbhandle]
 
 	set version 1
-	catch {
-		foreach row [$db query {
+	foreach row [queue dbquery {
 			select val from config
 			where var = 'version'
 		}] {
-			lassign $row x version
-		}
+		lassign $row x version
 	}
 	return $version
 }
 
 queue method update {_status {_log ""} {_retries 0} {_runtime 0}} {
-	set db [queue dbhandle]
-	$db query {
+
+	if {[queue dbaction {
 		update queue
 		set status = '%s',
 		    log = '%s',
@@ -283,22 +324,27 @@ queue method update {_status {_log ""} {_retries 0} {_runtime 0}} {
 		    runtime = %s,
 		    last = %s
 		where id = %s
-	} $_status $_log $_retries $_runtime [clock seconds] $id
+	} $_status $_log $_retries $_runtime [clock seconds] $id]} {
 
-	set status $_status
-	set log $_log
-	incr retries $_retries
-	set runtime $_runtime
+		set status $_status
+		set log $_log
+		incr retries $_retries
+		set runtime $_runtime
+		return true
+	}
+	return false
 }
 
 queue method set {var val} {
-	set db [queue dbhandle]
-	$db query {
+
+	if {[queue dbaction {
 		update queue
 		set %s = '%s'
 		where id = %s
-	} $var $val $id
-	set $var $val
+	    } $var $val $id]} {
+		set $var $val
+	}
+	return $var
 }
 
 queue method submit {{_start 0}} {