a problem about number()

XML doc:

JTYH_A001 A16:00 1540 finished finchina db2 2007-03-14 13:54:12.062 ......

the type of “” is string.
but i have to convert this node to a number, and compare them.

Xquery expression:

for $x in input()/XBridgeMessage
where number($x/property[@key=‘bocom.count’]) > 100
order by $x/property[@key=‘bocom.table’], $x/property[@key=‘bocom.timestamp’] descending
return {$x/property[@key=‘bocom.table’],
$x/property[@key=‘bocom.schedule’],
$x/property[@key=‘xbd.error.text’],
$x/property[@key=‘bocom.count’],
$x/property[@key=‘bocom.maxretry’],
$x/property[@key=‘bocom.retry’],
$x/property[@key=‘bocom.status’],
$x/property[@key=‘bocom.source’],
$x/property[@key=‘bocom.target’],
$x/property[@key=‘bocom.execute’],
$x/property[@key=‘bocom.timestamp’]}

when Tamino API calls this expression, it response a error.

maybe someone can help me.

thanks in advance.