Just replaced serpentine belt now warning light and alternator ticks

What is your question?

As it says in the title i just changed the serpentine belt on my grand prix and now a couple things are happening. First is that the charging failure warning comes on the display as well as a ticking sound coming from the alternator. I dont think i knocked anything loose and only things I did was take off the rezervoir and pushed the tensoner back. Car also kind of putters when starting up and every 4 or 5 times stalls out. I even tried putting old belt back on and still had the same problem. Any help would be awesome.