Critical Error: Odd Behavior on This particular Line all day

I have a procedure that has worked fine until today. Stepping through the entire procedure works properly everytime. Running it from start to finish however has given me a host of errors. I have not noted them as I have been looking for errors. But now this one is one I have never seen.

vba run-time error '-2147221080 (800401a8)': automation error

It is on a simple loop of all sheets w/in a particular workbook:
[VBA]
For Each wsnSource In wbSource.Worksheets
[/VBA]

erm perhaps post a bit more code?