Work on a branch and HEAD branch

[Riad Souleiman]

I have some problems to work on different branches.
Steps are :
- I create a new branch
- I make some updates without any problem
- I make a checkout on HEAD branch without any problem
- I make a modification and cvs wouldn't update the file on cvs
repository.
 The instruction is : cvs commit -m "bla" file.cpp
and the error message is : cvs [commit aborted]]: end of file from
server (consult above messages if any)
And there is no other message.

If I write : cvs commit
I have the message : cvs server: sticky tag 'HEAD' for file 'file.cpp'
is not a branch


I tried a lot of things and I don't know what to do else.
If there is any solution, thanks a lot.