Error in SMQ2 - Object requested is currently locked by user ...

HI together,

we send IDOCs from SAP R/3 through XI into an other SAP R/3 system (ORDERS). all messages will be processed but only 2 messages are get stuck in XI with the error message:

"Object requested is currently locked by user" in SMQ2.

Do anybody know a solution for that?

If i trigger the IDOC in WE19 again, the same error occurs again and again.

Many thanks

Alex