I tried it but it didn't work
I flashed 4.00.33 (german rom) to my device, copied the wmodem.exe file to an sd card, then flashed my device with 4.01.00 (t-mobile english rom) and copied the wmodem.exe file from the sd card to the device. I connected my xda to my computer with a serial cable, opened the wmodem program on the device, chose serial connection and hit start. I then tried to connect on my computer but nothing happened (no connection, no error message on the xda). For the record I currently use wmodem with the xda developers special edition rom flashed onto my device so I know that my settings are correct.
I'm guessing but perhaps there's a driver file for the 2003 version of wmodem.exe. I could not find any other file in the german rom that looked like it was associated with wmodem. Perhaps someone can determine if there is a driver file needed for this version of wmodem to run. If so, we can extract it along with the wmodem.exe file from the german rom and try again.