Check with the commands which, whereis which one you are using in interactive mode and compare with the one of cron (likely in /usr/bin or /usr/sbin...).
You may be using an alias also (to a more recent version...)
which svn --version
GNU which v2.16, Copyright (C) 1999 - 2003 Carlo Wood.
GNU which comes with ABSOLUTELY NO WARRANTY;
This program is free software; your freedom to use, change
and distribute this program is protected by the GPL.
---------- Post updated 11-07-12 at 02:23 AM ---------- Previous update was 11-06-12 at 09:38 AM ----------
thanks vbe i have figured it our with your help, when i was using cli to run it was using /usr/local/bin/svn while using cronjob it was using /usr/bin... so i have changed in my script to right path.