There could be many reasons why your Dimensions application has not started correctly but most of them will be due to the machine you're running Dimensions on itself.
The first thing to check is whether you are the only one who is having issues opening the application. If others are have had the same issue then this is most likely an issue with a recent update to your computers or security settings. Please contact your IT support department for assistance.
If you are working remotely and you are connecting to your work network using a VPN, please check that you are connected properly and that you are able to access your networked resources. If you have any problems please contact your IT support department for assistance.
The next thing to try is repairing the Dimensions application.
Open the Start menu and type 'Add or remove' and select Add or remove Programs.
Find the correct version of Dimensions in the list and select it.
Select Modify
Follow the wizard through the program maintenance and select Repair when given the option to either modify, repair or remove.
Complete the maintenance.
If these steps have not resolved your problem then a complete reinstall may be required. Please contact your IT support department for assistance with this.