newbie in CVS

situation:
I have a cvsd server running on Ubuntu, containing my VB code

Problem:
Most projects use the same very common classes (stored in directory "commonclass_directory").

I know I can use the ampersand(&) sign in the "modules" file for this, but how do I make sure that the "commonclass_directory" doesn't end up in top of the project directory? I need these common classes to appear in a sub directory, where VB needs them.

I tried out all combinations of -d, -a and what not options, and got very far.
Checking out two projects (both using this commonclass) appears to be fine, but committing a change in the second ends up with the message:

"cvs commit: Up-to-date check failed for `commonclass_directory/commonclass.vb'
cvs [commit aborted]: correct above errors first!"

(updating first says: cvs update: conflict: `commonclass_directory/commonclass.vb' is modified but no longer in the repository)

Please help me with my modules file (search everything and every help found states the -d and -a options as very obvious things to use).

Here's a clarification (used code to get uni spaced chars)
Obviously I want to be able to change, update, commit inside the commonclass_directory at will.

I don't think it's a good idea.
When someone work on say, Project 1, one will think that commonclass_directory
is owned but Project 1, and may be changed as ones wishes.

But those changes can break Project 2 !

So I suggest to have commonclass as independent project and install specified version on it to be used with Project 1, Project2, etc.

This way there is at least a chance, that when changes made to commonclass one will think about not breaking other projects.

Didn't mention it, but commonclass IS a seperate project. I needed to split the project up in two parts: one part that contains the project files, one other part that contains the *.vb files. This latter project (directory) is the one which needs to be inserted into Project1 and Project2.

It may be separate project, but if when you check out Project 1 it's subdirectory will appear under Project 1 dir still (almost everyone will think that it's part of Project 1 and can be modified at will and this change can break another project(s)

So ehm... how can I maintain these projects in the best way then?
Visual basic simply requires the code to be in that deep down directory, no way around that.

My suggestion:

In the repository you have:

Project1
Project2
...
CommonClasses

When you are working on say, Progect 1, you check out this project, EXPORT CommonClasses to any place you like/need and work.

Export will prevent you from occasionally check in changes in common classes.

If you need change CommonClasses you CHECKOUT them somewhere, work on them, make chek in. And then (if it needed) update CommonClasses used in the Project 1

By the way, are all your project is that independent ?
I.e if all of them are related to one product and all of them should be build/delivered together, than you have a much simpler solution:

Ok tnx, I think I can work with this suggestion.