Hi Singh.
1. SAP system kernel level is very old. you have to upgrade the kernel from NW 7.00 level 146 to 7.20 ext version based on SAP Basis SP level.
Refer the SAP Note
1636252 - Installing a 7.20 kernel in SAP Web AS 7.00/7.01/7.10/7.11
2. After that start the SGEN.
Regards
SS