CS4-Problem with creating symbols

I’m not quite sure what happened, but now, whenever I try to convert any object to a symbol, it puts it in the library, completely hides the object on the stage and puts the blue border with the registration at 0,0 in the top left corner.

Whats going on and how do I fix this? I can select the image (only if I remember where its at on the stage) and break it apart and it becomes visible, but that makes making movie clips impossible =\