XSL & PHP; Problem with xsl:choose

[loftinsulation]

Hello,
I have some xml, and have made some xsl to display the data in some lovely tables. This works beautifully on my development set-up (Windows, Apache 2.2.13, PHP 5.2.11), but fails on my hosted server (Linux, Apache 2.2.13, PHP 5.2.12).

Having done some investigation it is the xsl:choose statements in the xsl that cause the failure (yielding internal server error) on the hosted server.

Just wondering if anyone may know what is going on here?

Thanks very much.