(2006-09-07) Printer Cartidge Cradle Stuck

I bought an HP PhotoSmart-7760v Ink Jet printer. Since I have no real workspace at home, I stick the printer back in the box/closet when I'm not using it. I don't think it likes sitting sideways like that. For the 2nd time now I got an error message when using it: Print cartridge cradle is stuck. Clear jam then press OK. The printed manual doesn't help. See PhotoSmart page for outcome. http://static.flickr.com/96/238543064_88a091a906_t.jpg