What steps will reproduce the problem?
1. Enable Prat
2. Delete Combatlog.txt
2.  Enable the "ChatLog" module  (with prequisite reload)
3.  Turn on feedback of Prat Chat log messages (Turn off "Suppress feedback" in ChatLog module page)
4.  Disable Combat Log logging viat clicking "Toggle CombatLog" (with prequisite reload)
5.  /combatlog command
6.  Jump around a lot , Do some random crap
7. Logout

What is the expected output? What do you see instead?

Expected output is a combat log file with the stuff I just did (eg port to Theramore and jump around)

Wowcombatlog.txt with a size of 0. Modification date / time as expected but no output

And /combatlog command is used (both when CombatLog modules is enable or disabled

What version of the product are you using?

Wow client 3.1.3 9947 on OS X 10.5.7  PowerPC G5 Imac
*IMPORTANT* -> Can you reproduce the problem when ONLY Prat is running?

Yep

Do you play on US or EU. What language do you use?

US

Do you have an error log of what happened?

Test details done at : http://forums.worldofwarcraft.com/thread.html?topicId=17730153591&postId=177778292148&sid=1#5

Please provide any additional information below.

It would appear that regardless of if you actually have the "ChatLog" module even loaded it's preference of disabling the combatlog effects wheter the combatlog command works