Weird Error on Skill Tree

[Dogpatch 7]

Whenever I open the skill tree I get this message

 

 

It doesn't crash the client or anything but it's kinda annoying since everytime I open the skill tree it pops up. 

 

This is the 1st time I've seen it and have no idea what it is. Anyone have an idea?

My guess is lua error but I haven't touched the lua files in almost 2 months.

 

Changes I did before the error popped up:

Re-diffed client but the only diff I added was to enable "spaces" when creating a guild. I also tried putting back my old client and the same error pops up.

 

Thanks in advance.

 

Update:

Found out the same error pops up when opening a trade window

Update #2:

 

Fixed. It was a problem with the custom DLLs since my GRF is encrypted. Re-did the GRF encryption and it's fixed.

Edited July 18, 2015 by Dogpatch