Hi Sylvia,
It's good that you kept the original 2008 file. Sometimes we don't anticipate issues, and we convert a file to a new version without keeping a backup.
Do you have another computer you could install both, the 2008 and 2011 versions? If yes, after installing both, open them both. Open the 2008 file, and in the Legend & Overview pane copy your pushpin set, then paste it to 2011 window.
If the above copy/paste doesn't do it, then try the conversion again (open the 2008 file in 2011 program).
Laptop GPS World