In certain cases, the default XPath library might not suit your needs as well as other libraries would. You might want to consider using a different XPath library if: 

• Your tests use a lot of XPaths and play back very slowly.
• During playback, you see a browser error message such as "A script on this page is causing your web browser to run slowly. If it continues to run, your computer may become unresponsive. Do you want to abort the script?"

In these cases, you can configure SOAtest to use an XPath library that is faster or has greater support for the XPaths used in your testing. For details, see the discussion of PageController.xpathLibrary at Customizing Recording Options.