I have all the same problems and more described but thanks to your posts, I now understand that it's my HP printer somehow clashing with Excel 2010. I have a HP Officejet J6480 All-in-One.
Just so happened that I've always used a Freeware called CutePDF Writer. It creates .pdf files and after you install the program, it shows up as a printer.
My brainstorm was to set Cute Writer as my default printer since I don't have any other printer. I didn't uninstall or do anything with my HP printer, just left it there. I did disable loading the HP Solution Center etc. on startup but I don't know if
it makes any difference. In any case, I no longer have any errors when working in Excel. When I'm all done, then I choose the HP printer to print. Just make sure it's back to Cute Writer as default before you work in Excel after printing.
Not a solution, just a work around but at least it's not too difficult or time consuming. Hope this helps you get around the problems also.
Cute Printer