debugging macro switches to UDF which then gives #VALUE!

I have a UDF on a main sheet with about 5k rows that takes the name from another cell on the same row - removes some characters (middle initial, etc) and displays everyone's name in a particular format <lastname>, <First Name>.

I have some VB that runs on the same sheet and looks to that cell where the UDF is. Specifically it is this.

Please Login or Register  to view this content.

That pops an immediate Error 13 - type mismatch (avarsplit is declared as Variant)

When I'm stepping through the VBA line by line it has no problems until it gets to that particular line on avarsplit - then it tosses the Type Mismatch error and all of the fields in the column that holds the UDF changes to #VALUE! Sometimes the debug window switches to the UDF module.

Either way there's no way to get back the values unless i totally exit out of excel and reopen - and then it'll just toss the #VALUE! again. Has anyone run into this before?

For reference my UDF is this

Please Login or Register  to view this content.

I recently added the on error resume next and the application.volatile.