External NTFS drive goes read-only bug

After for working well for ages on my MacBook Pro, this 1.5TB WD Elements drive has changed to being read-only. Which is weird because I've been using it for ages, even had it set as my iTunes music folder so not being able to change the disk is a pain. Also I have NTFS-3G installed and it is working to access another volume called "PC" which you can see has "custom access" whatever that is. I can write to this disc fine, but not the other one (Elements). Not sure what the next step is. Running OS X 10.5.8.

so