27101, 00000, "shared memory realm does not exist" // *Cause: Unable to locate shared memory realm // *Action: Verify that the realm is accessible
This error message indicates that you have some systemic issue. I'm going to take a guess and say that it may be related to the fact that 8.1.7 isn't supported on Windows 2003. From memory, the first Oracle database version that was supported on Windows 2003 Server was 18.104.22.168.0 (that's 22.214.171.124.0 with the 126.96.36.199.0 patchset applied -- the patchset is required for Windows 2003 support). Before anyone can help, you'll probably have to upgrade the database to a supported release.
This was first published in October 2004