mid function causes a compile error

[Brotherwarren]

Hi all, I have a problem that I cannot solve.
I have a routine that prints various registers for groups of pupils.
the routine checks each of the controls on a userform
if the control is a checkbox and its value is true then the caption of
the checkbox is analysed.
This is where the problem occurs. I am using the following code,
whenever I run the sub, I get an error message along the lines of
"compile error: cannot find project or library"
Here's the code -

For Each thing In RotationRegisterForm.Controls
If Mid(thing.Caption, 1, 2) = "11" Then
ActiveSheet.Range("rotStart11Dates").Range("a4").Select


the rest of my code follows

I'm not sure what to do about it.
Also whenever I am naming a range of cells in excel I get an identical
error message to the one above. Is the problem caused by one of the
names I have chosen for a range?

 

[Andrew Taylor]

This kind of error usually means that the VBA project
has a missing reference. From the VBA window select
Tools/References, and look for any items marked
"Missing". Clearing the checkboxes for these may
solve the problem: if you get new errors saying
"Unknown Type" or similar then you may need to
reinstall some DLLs.

 

[Guest]

See answer to later posting of this question.

 

[Brotherwarren]

many thanks to all those who replied. Tom Ogilvy's approach of
qualifying MID with vba. prefix helped! Cheers again.