As we found out, sometimes only clearing cache in client or browser directly might not be enough to solve certain problems in game.
If you still have problems with fights in game (such as not being able to leave a fight or attack a mob etc) follow this procedure:
For temp files issue:
Step 1: Game Client: Log out of the game client, select error> delete obsolete files and clear cache
Step 2: Go to Control Panel computer settings> Network and Internet> Internet Options> Delete browsing history and cookies
Step 3. Open Internet explorer click on settings and click on delete history and temp files
Step 4. Repeat Step 3 process for all browsers on your pc example: Chrome, firefox
This will clean all history of the game from your computer.
Once you have completed all of these steps re-launch the game in Client or Web Browser of your preference and see if you have any more troubles.
Thanks and Good game!
PS: Great big thank you to Queen of Death who figured that out and already was able to help quite a few desperate player in game ... including me