Hi RK,
You say in your query that you have not defined any PDCH for EDGE. If there is no dedicated PDCH for EDGE then the system will be allocated with BPDCH (Basic Packet Data Channel) where in only GPRS will be enabled. Also, the BPDCH will get enabled only when there is a vacant TS which is been dedicated for CS trafic.
PLs try allocating 1TS dedicated for EDGE.