PLC - couldn't Complete Task

System

Hi,
I'm using PLC to publish out-of-box 'Component Guide' site. It went through till Review Files. After a reviewer Approved Changes, I logged in with the initiator account. I can see an open task listed as the attached screenshot, but there is no echos when I was trying to input some Complete Task comments and 'Finish' button was always in grey. Acutally it indicates 'This task doesn't require your interaction'. Then how can I move ths workflow forward? Any particual configuration in PLC? Thanks very much!

- Env: TS7.31, OD Base 7.31, LSDS 7.31, MySQL 5.5. All are on the same Windows 7 Virtual box;
-A few changes in PLC used configuration files are in /conf/livesite/*metadata.xml to point to right database. Another change is in /etc/odbase.xml to enable database deployment. All other configurations are intact.