LocostUSA.com

Ok, so I keep getting a 403 error when trying to submit, preview, or save a post/reply/new topic, or send/preview/save a PM, yet there is no indication that the forum software is actively trying to prevent me from posting (ie I can still see every forum/see attachments and the menu at the bottom of the screen says I can do all the things it lists), nor have I received any indication from any moderators/admins to point to a similar conclusion. Any idea whats up? If it matters, every time I've tried to post recently has been from an Android-based tablet, I haven't tried posting from a PC/Mac yet

EDIT: strangely enough, it let me post this... it may turn out this is all a case of my having seen the proverbial ghost of the phpBB world

EDIT2: I just tried posting in a thread in the builder's log forum, and got the 403 error again... seems I have a problem with posting replies, but I'm able to post a thread?

If this goes through, I guess my problem is solved, but any idea what caused this in the first place?