Its probably from the Pixel Fighter Community.
BF1942CF (Battlefield 1942 Compatibility Fix) is a Microsoft Application Compatibility Toolkit fix database (.sdb file) in an executable installer.
This sets only the individual compatibility fixes necessary to run BF1942 with FH in Vista and Win7 without invoking the complete OS compatibility mode. The full mode contains a long list of fixes that aren't required for BF1942 and cause unnecessary system restrictions.
The other useful feature of using a tailor made fix is that it is not seen by PunkBuster as Win98 compatibility mode, which was excluded by evenbalance and will cause kicks from PB enabled BF1942 (and thus FH) servers.
I've actually recreated it myself using the MS toolkit and the only fixes required are:
EmulateHeap - emulates the functionality of the Windows 9x heap manager
NoGhost - no window ghosting
Win98VersionLie - Hooks the GetVersion and GetVersionEx APIs so that they return Windows 98 version credentials
For the full low-down on running FH 0.7 in Vista and Win7, the PFC site is the place to visit.