I am getting the following error:
Microsoft VBScript runtime (0x800A000D)
Type mismatch: '[string: "MND3"]'

at the following line of code:
CCID = Right(Request("CourseNumber"),Len(Request("CourseN umber") - 3))

It's a simple problem: as part of a data string I am receiving an identity (CourseNumber) that is either one or two numbers long and is sometimes prefixed by the letters MND
(say MND3 or MND62). I need to strip the MND out and use only the numbers. The code used follows:

If Left(Request("CourseNumber"),3) = "MND" then
CCID = Right(Request("CourseNumber"),Len(Request("CourseN umber") - 3))
Else
CCID = Request("CourseNumber")
End If

The logic seems sound, but I am getting the type mismatch error.

Any ideas how to fix it?

It seems as though you've got your parens in the wrong place.
I've modified your code to put the parens in correctly:

CCID = Right(Request("CourseNumber"),Len(Request("CourseNumber"))- 3)

You might be right. In fact I believe you are!
But it still has not fixed the problem. i am still getting the same error.

I'm not seeing anything else wrong with your code.
You're getting the same error on the same line? Did you edit your code exactly as I've posted it?

Yes, exactly.
I'm wondering if I need to convert the resulting numbers to an integer. If you cut MND3 to 3, it's still a text string, right?

In ASP, everything is treated as a varient. Usually when you get a type mismatch it's because your trying to do math on something that contains something other then numbers.

To answer your question, if you cut MND3 to 3, it's still a varient.
If you add 6 to it, it will be treated as an integer. (3+6).
If you concatanate something to it, it will be a character. ("the number is " & 3)

Try displaying all your variables and see if your getting what you expect. Watch for NULLs as they can be a nusiance.

Try breaking up your code into smaller chunks to see how it works and exactly where it's breaking:

tmp1 = Request("CourseNumber")
response.write tmp1

tmp2 = Len(Request("CourseNumber"))- 3
response.write tmp2

tmp3 = right(tmp1, tmp2)
response.write tmp3

Hope that helps even a little.

Thank you. i'll give it a try..

Boy, do I feel like an idiot. Your parens correction actually fixed the problem. But I applied it to a COPY of the code instead of the live code, which was why I kept getting the same error over and over. A five minute walk in the rain fixed my head problem.

Thank you so much for your help!

I'm glad it's working for you now.
It usually is the simple things that get ya. Sometimes just getting away for a bit allows you to come back and see things with a new perspective, allowing you to pick up on things that got overlooked the first time you looked at it.