Well, I installed DNN 4.8.0 with SQL Server 2005 on a Virtual Machine to test your configuration. I then installed helferlein_Form 01.04.02, and I did not get the mentioned error. I also tried it in different configurations - with object qualifier, without object qualifier etc. - everything works fine.
In the meantime I have also read that godaddy is very restrictive and the installation of DNN is not really trivial there. Please refer to the DNN forums how to install DNN on godaddy.
Anyway, I also recommend to update to DNN 04.08.01 or better 04.08.02 because of security reasons.
Best wishes
Michael