cannot check in modification

Using HelpStudio 3 to access a subversion repository
edited local checkout file
keeps saying file modified , which it is and I want to check it back in
but keeps asking to revert which if i say yes to will revert to file saved
in repository
if I say no to file is not sent to repository and remains checked out

what do I need to do to check it in

if I use Tortoise to check it in all works ok


just the use of the proxy does not work


any ideas