1. Boot the machine into safe mode
2. Take the extra.dat file mcafee is providing and load it into c:\program files\common files\mcafee\engine
3. Copy svchost.exe from c:\windows\servicepackfiles\i386\svchost.exe to c:\windows\system32\svchost.exe and c:\windows\system32\dllcache\svchost.exe
This should remove the faulty signature and replace the damaged svchost from the the servicepack files. This test has been tested and works within our company. We have rolled it into a quick exe package for ease of use.