Fatal error: Call to undefined function

This is almost always a symptom of version problems with a contrib module (or theme)

This is most often seen in form functions -undefined function: form_*() but could result from any missed upgrade step listed in the module developers upgrade notes which lists the deprecated functions, but most likely means you have installed the wrong version of the module (or that a compatable version doesn't exist yet).

You may find that turning on legacy.module will support a few of the older (deprecated) functions that the troublesome module is trying to call.