Installing Web Access on Exchange 5.5

I installed Exchange 5.5 on a Win 2K member server almost a year ago & all went well. I am now trying to install Exchange 5.5 on a domain controller & I keep getting an error when trying to install the Web Access componant. The error is: The requested control is not valid for this service. ID:0xc002041c This happens when I install it from scratch or if I try to install it via Add/Remove features. Please help?

 

Is IIS installed?

 

Yes - If you type www.nirimba.net in your browser you'll get to my webpage & ftp - There will be a link to what was web mail.

 

Are you using the service account?
Is SSL setup and properly configured?

I point this out, although i don't know if its entirely relevant.
http://support.microsoft.com/default.aspx?scid=kb;en-us;246286

 

I don't think SSL is configured as I wasn't going to use it & I didn't ahve to configure it before. I had a look at the link & all it says is to reinstall Exchange which I've done a number of times.

 

all it says is to reinstall Exchange
It also makes a reference to blowing away the registry keys via KB259158.

 

Oops - I see what you mean about removing exchange completely. What about mine & other users mail? What directory does it live in, what directory do I need to back up?