The most important thing to consider is the Raid Controller.
Are they similiar? I think the 2800 will be a Perc 4 controller but not sure about the 1150!
In relation to the error you got in relation to "load dll's":
Check if the 1150 server was upgraded from 2k to 2k3.
If it was it is possible that youre installation Directory for windows will be WINNT not Windows. This will cause this error.
So basically. When you load windows 2003 you are probably taking the Default install folder: Windows instead of Winnt.
Check the windows installation Directory on the 1150.
Gilly