Simple Passcode not working after iOS 5 updated

I had installed iOS 5 on my iPad 2 and it worked fine for awhile. Today I noted that the usual passcode didn't work to login and was completely messed up, but I didn't change the passcode.I tried using my "exchange" password which I used to set up my "Exchange" account on my iPad so I could access my work calendars and email. My iPad unlocked. Then I went to Setting, turned on "Simple Password",