Using as a parser function generates server error

[mr.chad....@gmail.com]

I'm running MW 1.30.0 with PHP 5.5.9-1 and MySQL 5.6.34. In installed the extension using the instructions in the For REL1_31 and earlier section.

When I invoke a widget as {{#widget:blah}} it generates an error in the preview. Trying to save the change generates a 500 error and the change isn't saved. ParserFunctions is running and $wgPFEnableStringFunctions is true.