Hard to say without seeing the File > Export > Puppet, but agreed - it looks like from here the arms aren't independent or properly separated since the belly seems to be pulled by the arms.
I'd download Wilk from Okay Samurai Puppets - open up the included .puppet file, select the puppet in your project panel, and hit cmd + e (mac) / ctrl + e (pc) to open up the master Illustrator file. Note how his arms are grouped and organized, as separate groups inside the body and each with a + in front. You'll need to do the same and staple them at the shoulder to work properly.
See https://youtu.be/_smLXODTd6U?t=29m7s for how Wilk's arms were set up. If you follow that you should be in good shape.
Ok! I'll try that
Alright I fixed it! I wasn't using staple! It works now!