Hello Harish,
not sure what do you mean with RCP I guess you mean remote copy protocol.
usually what can change in using two devices in different IP subnets is that some mechanism of discovery may fail if it is based on broadcast this is typical of MS networking.
And in that case the ip helper-address can help.
But RCP is based on TCP and it is used on unix systems.
A possible issue may be that one unix server thinks the other device is in the same IP subnet (wrong netmask).
This issue can be addressed using ip proxy-arp on SVI vlan interfaces of C6500.
A packet capture may help in understanding what is the problem.
Hope to help
Giuseppe