I don't think the DSC-WX150 is completely PictBridge compatible. If your printer can has a compatible memory card (MS Duo or SD/SDHC/SDXC) reader, then you should be able to print without connecting the camera to a computer. The manual only lists printing still images from the memory card or after importing the images to a computer. See http://docs.esupport.sony.com/dvimag/DSCWX100_WX150_guide/en/contents/09/01/01/01.html .
I hope this helps.
Cindy Wells
Out of curiosity try different working memory card. See if it works with that one. If it does, then it appears something went wrong with your memory card. If it also does not work see if you can play back a file from memory card 2. If that works then it is a record issue with the camera. In any event it is not a good situation. Sony products are notorious for being difficult to fix and expensive to repair. Hope it is the memory card - they do go bad.