Run-time error 91
Object variable or With block not set

I keep getting the above error when the 2nd line of code runs. I dont
know why. I dont know if this helps but I had to use the InStr
function in order to quit getting an error in the 1st line of code.


FoundCommentCode = Trim(Left(ActiveCell.Value, InStr(ActiveCell.Value,
":") - 1))


TargetCommentCodeAddress =
Worksheets("Questionnaire").Range("P1:P2000").Find (FoundCommentCode).Address


Also I dont know if this will help but here is some other info:
This problem code is in a module in a a public sub that is called from
a Worksheet_SelectionChange precedure in the worksheet module.



Thanks in advance
Todd