Profroma Invoice Error in GTS

Hello All,

Proforma Invoice Transferred from ECC to GTS , and customs document was generated . But i was not able to print the customs document. Following are the errors

1 Executor/Sender has not been maintained in customs document xxxxx

2 business addin /sapsll/form_proc was not called

3 Printing error

4 Action could not be successfully executed.

Please help, we are on GTS 8.0 version, ECC 6.0 version.

Thank you all