yeah I am having the same issue. Here is where I prob went wrong.
Just installed Vista 64bit (was running Build 7100 Windows 7 64bit)
I backed up my COD W@W Profile and backed it up.
I installed all my stuff and transfered my profile, everything was cool.
Then I installed my Retail Disk of COD. Patched 1.2 first, 1.2-1.4 2nd and 1.5 third.
After that I started my game. Logged out, went and restored my backup and everything was fine.
You know how sometimes you find an old game or you install a program you have not used in a while? Well i installed my backup of Steam.
Once I logged into Steam I guess the Steam Copy of COD W@W over took my account. I lost everything. So I uninstalled my retail disk version, erased my local profile and started from scratch.
Now after I reinstalled everything I am now getting the same code mentioned at the beginning of this post. I hope that give an idea of whats up.
Hit me back if you guys find a fix b4 I do email@example.com
or MSN firstname.lastname@example.org