Getting the "Insufficent Error" with Dataguard

[Bogey]

I'm getting the error

Error
Insufficient disk space.

when trying to use the EM dataguard feature. So I logged on to metalink and downloaded the patch. I tried installing but I'm getting the error
OPatch detects your platform as 912 while this patch 3895311 supports platforms:

215 (MS Windows Server 2003).

Any clues on how to get the dataguard working??

thanks.