Narayana,
Can you share your BW and BPC SP and version?
Here are some troubleshooting options in the mean time:
1. Have checked the short dumps on the server to see if you can get more information on the error (T-code - ST22).
2. Check which file extensions (ALLOW_EXTENSIONS) and file sizes (ALLOW_FILE_SIZE) are allowed on the server under Globalparameters. (T-code SPRO ->SAP reference IMG -> Planning and Consolidation -> Configuration Parameters -> Set Global Parameters.
Good luck and let us know how it went!
Akos