Thanks Jason. You were right, the limits were not being raised. Although I changed the settings on the php.ini in the public_html directory, these were not getting applied to the Admin sub directory. I copied the php.ini there and it seems to be working. I thought the php.ini in the root would automatically get applied to sub directories but it seems to depend on the way the server is configured (HostMonster) and my config requires the php.ini be applied to all sub directories.
Thanks again for the solution and the quick response.