[otrs] Can't find Unicode property definition "r"

Hi,   OTRS stopped fetching emails. It has happened twice in last 3 days. On checking the logs it was found:   [Fri Aug 13 13:38:49 2010] [error] [client 192.168.1.20] [Fri Aug 13 13:38:49 2010] index.pl: Can't find Unicode property definition "r" at ../..//Kernel/System/PostMaster/Filter/MatchDBSource.pm line 70., referer: http://192.168.1.15/otrs/index.pl?Action=AdminMailAccount   When i removed the suspected email , the issue was resolved.   Please tell me why is it happening and how can I resolve this issue.   regards, amit