error codes are always accompanied with a message that explains them. The message is provided in a standard way: For QuickOPC-COM, through IErrorInfo interface; in QuickOPC.NET, in the Message property of the exception object.
Error 0xC004EA05 means:
Run time is over the limit. The license you have (most likely trial version) does not provide valid data after certain time period expires. Note that after the component's process is simply restarted, valid data will be provided again. Obtain and install proper license to resolve this error.
Attached to this post I have included a header file with more error codes and their corresponding messages.