No account assignment exists; enter an account assignment

While transferring a Purchase Req from ECC to SRM, I am getting the below error in SRM under SLG1.

No account assignment exists; enter an account assignment

Since we are transferring a Plant stock, I assume that no additional account assignment is required in ECC. SInce we are using PPS module, the Fund Center, Fund, Functional Area, Budget Period, Grant, Commitment Item is populated in ECC under Account Assignment area within ECC.

We are using SRM 7.0 Ext Classic Scn with ECC 6.0.

Please provide some help.

Thanks

Jancy