Battery Charge indicator light appeared, please help!!!

[ace93rd]

Hi all,
Yesterday when I was driving home from work I noticed that a little red battery symbol, indicator light (which indicates the battery isnt being charged) came on, my stearing got stiff and the temperature guage began to rise as the engine started heating up.....I looked in the manual and it says that this symbol has to do with battery not charging and mentiones that there could be a problem with the V-belt alternator...it also goes on to describe the symptoms such as stiff stearing and engine heating as result (which I had both). My question is has anyeone else had this problem and know what it is caused by?? A couple days ago i got locked out of my X5 and a locksmith opened the door...could he have messed something electrical up that causes this problem. Any thought and ideas would help greatly.
Mike