Dhalia

PLEASE HELP! i have just started and ran the server, it worked normally, my friend could go on it too. However when i added plug-ins i think this is where it went wrong, when i go on the file part, i go in plug-ins, and see the normal list with a file icon next to each, however as i scroll down, the list is copied but with like a sign that you'd see on a road with a 'dont go over the speed limit' or do not touch, or a simple no.... im highly confused please help.