When you attempt to uninstall Exchange (version 5.5 SP2) from SBS 4.5, you receive:
Entry Point Not Found
The procedure entry point [email protected] could not be located in the dynamic library GAPI32.dll.
The problem is that the unistall runs setup from the SBS CD-ROM and this causes Gap132.ddl to be loaded from the CD_ROM. Unfortuneatley, the version on your HD came from SP2, while the CD-ROM one is from SP1.
To perform the uninstall:
Rename c:\winnt\system32\gapi32.dll *.old
copy <CD-ROM:>\server\setup\I386\gapi32.dll c:\winnt\system32
Then perform the uninstall.