2003 SBS doesn't start after mirror

hello list,
ich have a strange problem:

I have two Acer Altos G301 Server with onboard IDE raid
controllers. On the first I installed 2003 SBS without any
array functions, because with ide raid it doesn't run,
without it works fine.
For security reasons I mirrored the system on a second hdd
with the build in raid controller => no problem.

But when I try to start the copy in the second server
(identically hardware) it hangs up, before switching to the
logon screen. In safe mode it boots.
If I try to start the copy in the original server hardware
where I done the mirror, it starts!

Any suggestions?
Especially anyone with Acer Altos G301 expirience? The
german Acer support don't know 2003 SBS.

Thanks in advantage!