General :: Runtime Error - When Filter Returns No Results

I'm creating an item look-up form with 2 criteria that I wan't to auto-filter as the user types. I'm placing my code in the Change event of the textbox, and only calling the .text for the current textbox (.value or no property at all for the other). The filter works smoothly and as intended until it returns no results in my table, and then it pops me with the error. I've tried forcing focus to the textbox in different places throughout the code, but to no avail. If I use the .value or no property for the current textbox, I'm not getting the CURRENT text, but the old text before it was changed, so the filter doesn't work properly.

Private Sub txtVendor_Change()
Me.FilterOn = True
Me.Filter = _
"((strSearchVendor Like '*" & Me.txtVendor.Text & "*' AND strSearchItem LIKE '*" & Me.txtPartNum & "*'))"
Me.txtVendor.SelStart = Len(Me.txtVendor.Text)
End Sub

It usually pops the error on the last line "Len(Me.txtVendor.Text)", but I've had it do it on the Me.Filter line as well (only when debugging and messing with next statement placement).