This is the peril of using those all-in-one tools that do all the thinking for you. Unless you already know how they're going to work, you may end up with problems.
Your best bet is going to be grabbing an appropriate copy of PHP 5.3.2 and installing it yourself. 5.3.1 no longer seems available for download, probably due to many security fixes in 5.3.2. 5.3.2 seems to contain the XSL extension.
Don't even think of taking the XSL extension from 5.3.2 and trying it in your 5.3.1 copy, the results are likely to be crashtastic.