Yeah I bought bf2 sf the other day and Have had exactly the same problem.
I purchased and downloaded sf
During the instlall i got the same md5 error
at about 64% the game either closes or crashes with this error
"memory.dll: sanity check: block size -2013264896 (2176.00 MB) doesn't seem sane"
reinstalled bf and same error comes back... lost my controls for nothing
d21storm: Please tell me if you find a way to fix this...
/me waits impatiently for any ea help