Error in FBS1 - WBS Element not allowing....

Hi Experts

Ours is an Upgrade project from R3/4.7 to ECC 6.0.

We have created the Screen Variant Z004 in T.code FBS1 for Fast Data Entry.

After upgrade, I am trying to post the data by using this Z004 Screen Templates in G/L account items fast entry and the system is throwing the error that "GL Code XXXX need Co Object" eventhough I have entered the WBS element as CO Object.

System is successfully posting the entry when I use the Standard Layout and also in normal mode instead of Fast Data Entry.

In the R3/4.7 environment the system posts the document successfully by using the Z004 screen Template layout.

Is it happening because of Upgrade and how to overcome this error?

Can you please guide in this regard?

Thanks in advance

Priya Mahajan