Importing Contacts

I can not get the CRM to import my contacts. I does everything up to actually importing the data and it gets stuck. Nothing imports. I was able to import the data on the on premise version but the On demand version would allow it. Whats up with this? anyone else having trouble? I have imported Products with no problems.

Any advice would be great...I am killing myself, 4 hours of trying and I am getting frustrated as hell.

James