Players can't do crap!

This is by far the weirdest thing to ever happen to me with my MineCraft server. I have not even been inside my config file for PermissionsEx or updated my server or updated the plugin in a very long time, I have done nothing but simply play on my server. So one day I went on and I'm OP on my server obviously so everything was cool for me but a player came on and could not talk or destroy blocks or anything! Now I know this is the difference between being OP and not being OP because I deopped myself and tried typing in the chat and nothing appeared, I even tried destroying blocks and I could not do that either. What also makes this weird is because the chat does not display any error messages for example "You don't have enough permissions" nothing appears at all. I use PermissionsEx and I had it all configured perfectly with modifyworld.chat and modifyworld.* a while ago so it should be working but its only working for OPs. I need to fix this problem soon because I'm loosing players fast because who wants to play on a server where you can't talk or build . The only thing you can do is walk. So plz, someone who might have an idea of what is going on, help me. Thanks in advance!