NMatrix

I have a schema that uses current() function that was working well, but now (it seems depending on the input xml file) fails???? Any ideas on what could be going on? My Schema is below. I did change the structure of my xml slightly.

<schema xmlns="http://www.ascc.net/xml/schematron">
<title>RAID Prereq's: Drive Connection Types Same</title>

<pattern name="checkSame">
<rule context="DriveBays/DriveBay/Drive">
<assert test="count(//DriveBay[Drive/@ConnectionType=current()/../Drive/@ConnectionType]) = count(//DriveBay)" >
DriveBay Drive Connection Types Should be the Same.
</assert>
</rule>
</pattern>

</schema>

I'm really puzzled by this: Also I get weird errors in schema files complaining that a exslt function was not found on xpath i'm using a count only?

thx kim