"400 Bad Request" on commit with TortoiseSVN 1.8.5 t to Subversion 1.8.8

Dear Support,
Suddenly all the team not able to commit any thing to our server due to "400 Bad Request"
I don't know what is the reason!!!!

I tried to Google for how to solve the issue, and I found someone in the below thread, said you need to stop "SVNAdvertiseV2Protocol Off "
I don't know , which config file I need to modify this property and I am not sure whether it will solve the issue or not ..

http://qnalist.com/questions/2806524/400-bad-request-on-commit-with-1-7-client-to-1-7-server

SO PLEASE SUPPORT ME URENTLY

Here is my SVN details
TortoiseSVN 1.8.5, Build 25224 - 64 Bit , 2014/02/18 20:05:11
Subversion 1.8.8, -release

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             Maha Hussein Sallam
             Middleware Team
                      T : +971 4202 2415
                      M : +971 56 9583786
                      E : mmaha_at_etisalat.ae<mailto:mmaha_at_etisalat.ae>
                      C : Asset Gulf FZ LLC

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