Error within webforms when using the event webform module

I'm getting the following error when I add elements to my webforms:

warning: array_merge() [function.array-merge]: Argument #1 is not an array in D:\Documents\sites\networkforpractices\sites\default\modules\event_webform-5.x-1.x-dev\event_webform\event_webform.module on line 162.

The error disappears if I disable the event webform module.

Any suggestions?