Consider redeploying the engine to the recommended deployment location, the \Windows directory. UltraLite automatically looks for the engine files in this location.

If you have install the engine to any other location, ensure your connection code uses the START connection parameter.

If you have used the START connection parameter, and you are sure the path to the engine is correct, ensure you have used the correct escape sequences for special characters in the path name.

For example, in some cases you may need to change this code:

ULConnection conn = new ULConnection(@"dbf=\Program Files\HelloEngine\HelloEngine.udb;
START=\Windows\uleng11.exe")

To something similar to:

ULConnection conn = new ULConnection(@"dbf=\\\"Program Files \"\\HelloEngine\\HelloEngine.udb;
START=\\Windows\\uleng11.exe");