It keeps telling me at the bottom of the screen that the displayed transactions may not be correct! You may need to upgrade, or other nodes may need to upgrade. Can anyone help me please?

i am using a mac os x version 10.6.8 and i have tried to upgrade the bitcoin wallet using bitcoin-0.8.1-macosx.dmg but after a restart it will not open the wallet unless i go back to my previous version. :-(

any help will be greatly appreciated. :-)