Sudden Strike Forever is protected with the CopyLok/CodeLok protection.
r!sc has created PoxyLok which will unwrap the exe - nice one r!sc
Download from ####://www.cdmediaworld.com/hardware/cdrom/cd_utils_8.shtml
PoxyLok can extract the real executable from the protected file, just replace the existing .EXE and burn it back to a CD-R or replace it after the game installation.
Hope it helps.