Property tab builder closing

Hi everyone, ran into an issue today and cant find a fix anywhere..

I have been working on making a BOM template and have been using custom properties to fill it, quite successfully! 

Until now, I open the property tab builder application, but when I open the BOM template custom properties that I have been using, the application just closes with no errors or loading... 

Issue started this morning after editing the tab builder to include materials...

Any help on this as I have been scratching my head for a little while now - Im running on SW2015 if this changes anything

SolidworksGeneral