The first step with any problem like this is to make sure you have the latest version. Older versions may have trouble updating

To install the latest version:
First we recommend uninstalling what you have before reinstalling. If you're a full version user you will automatically be upgraded to the full version when it installs, and don't worry - Dream Aquarium will remember what your current tank setups are so you won't lose your settings.
To get the latest installer click here
If you have tried the latest installer and are still having issues, please contact us or see our troubleshooting guide.