Are you unable to equip a weapon?

First, check to see of your base stats are where they should be. For example,

Item: Sword
Str:100
Dex:50
Luk:20
Int:0

Your goal is to match those stats. For example,

Your Str is:

120(90+30)

Do not worry about the (+30).

Make sure you base stat (90) is up to 100.

Hope this helps.

*Edit* If you do meet the requirements, try logging out then back in to see if it fixes your problem.