This happened to me when I installed S60 SDK for 3rd edition beta. I am using Codewarrior v3.1 Personal. After installing S60 SDK for 3rd edition beta I was happy to see that even the *.h files were being included in the file list when using the 3rd ed SDK. However when I try using the S60 SDK 2nd ed FP2, a *.pref file is created in place of the MMP file with only the ff details

UID 0x100039CE 0x10005B78

Not having an MMP file prevents me from re-importing the project. Removing all the SDKs and reinstalling S60 2nd ed FP2 and Codewarrior would solve the problem. Does this mean I will have problems working when both S60 2nd and 3rd ed beta is installed in my pc?