I'm running an xslt transformation in OSB. It invokes the current-dateTime method as follows:
<db:lastupdate>
<xsl:value-of select="fn:current-dateTime()"/>
</db:lastupdate>
It returns the following error:
<con:fault xmlns:con="http://www.bea.com/wli/sb/context">
<con:errorCode>BEA-382513</con:errorCode>
<con:reason>
OSB Replace action failed updating variable "body":
javax.xml.transform.TransformerException: Instance method call
to method current-dateTime requires an Object instance as first argument
</con:reason>
...
</con:fault>
The function current-dateTime() is available in XSLT 2.0 but not in XSLT 1.0. So the chances are that when it failed, you were using an XSLT 1.0 processor.
Note that the fn: prefix is never needed in XSLT. If for some reason you want to use it, you must declare the namespace - but there is absolutely no point. Just write current-dateTime() without the prefix.