I have both versions. I have the DVD version on my main machine, and I bought the EA Link version for LAN play on my secondary machine.
All I did to solve my problem was to copy all of the files from the root of my EA Link version over to my main machine, then renamed BF2142Pace.exe to BF2142.exe and VOILA! No more DVD
(and EA Link doesn't even load
)
There must have been a couple of files I needed other than the exe and swiffplayer.dll