So if you've landed on this thread looking for a solution suitable for a newby, here's what worked for me without needing a command line or great knowledge:
Open "Ubuntu Software Center"
Click on "Installed Software"
Search for "nvidia"
Remove all resulting packages except for "jockey-gtk" and "jockey-common" (remember them in case you want to reinstall after the upgrade)
Try the upgrade again.
This worked to get me from Lynx to Meercat when I ran into the errors described above.
So if you've landed on this thread looking for a solution suitable for a newby, here's what worked for me without needing a command line or great knowledge:
Open "Ubuntu Software Center"
Click on "Installed Software"
Search for "nvidia"
Remove all resulting packages except for "jockey-gtk" and "jockey-common" (remember them in case you want to reinstall after the upgrade)
Try the upgrade again.
This worked to get me from Lynx to Meercat when I ran into the errors described above.