Nokia :: E52 Phone Restarting While Inserting Headphones

I recently brought a new nokia e52 and wantd 2 hear its music quality. I inserted my headphones pin in the jack only half not knowing that it should be fully inserted. I started playing a song but was unable 2 hear anything and it restarted automatically. I tried inserting it fully but it didnt work out until my brother showed me. I did this thrice and the phone restarted thrice. Now it goes fully into the jack. So is there a problem with my phone or is it normal coz now i can insert it fully and listen 2 my music clearly.