TREX 6.1, 0021 error

Hi,

We have installed TREX 6.1. Checking setting, we found the following error:

Optimize call exception    0

For CatID:41C7FDF17FB0668FE1000000980964C8

Language: E

Return code: 0021

The return code 21 correspond to the flowing error (Sap note n° 450226)

21 = Search Server could not retrieve data because this row is locked

Do's any body know how to resolve this error please.

Thank you in advance for your help

Noa