Cannot check in file after branch...?

[Flossie]

Hi, I'm a bit of a CVS newbie, and have been trying all sorts of things.
I have CVS installed on linux, and my client is TortoiseCVS running on 
windows XP.
As a test I had a modified local file (i.e in my 'sandbox'). I then 
created a new CVS branch, and chose to ignore any modified files 
currently 'checked out' (not usually something I'd like to see happen, 
but is likely to in the real world).
After this, I found I couldn't commit the file - messages are:

cvs commit: sticky tag `1.4' for file `test1.txt' is not a branch
cvs [commit aborted]: correct above errors first!
Error, CVS operation failed

I can't figure out how to get the file back into CVS. As far as I'm 
concerned, the file should happily be able to be updated in the main 
code tree (i.e ignoring the new branch), afterall this is where it was 
checked out from.

How do I do this?

TIA