[imp] IMP / Horde Problem

[sc2 at gmx.at]

hello
yesterday i have mailed about the login problem now i have little more
information.
Auth over Imp >>
sub.domain.com/login.php >> redirects to a page (i wish i could say
where.....) and then it follows a failure for DNS/Server, so it must a
domain where it redirects that does not exists (so it would follow a 404/403
apache/server error)
Same when i go over imp/login, this works fine but after pressing login,
then same failzure where is the redirect linking?
thanks!