Isn't HP able to write working drivers?

Because the old printer was not working anymore I had to buy a new one. It was a HP Photosmart C5380. But it gives me no joy, because the Mac drivers have a big bug. Showing the ink levels, printing test pages and stuff like that works without problems. However, if I try to print from a normal program, I get the error message "USB class driver missing.". Therefore, I wrote to the support and they told me there might be different reasons for this error message, but in may case the problem is that I'm using a case sensitive file systems. These are not supported.

IMO such mistakes should not happen in a big company like HP and if these should be fixed as soon as possible. For me it seems that there are only written some file names in the source code in a wrong way and this should be now big deal to fix.