Error during Windows startup. I have Windows 98 platform and whenever I startup windows I get an error.

And the message says:-
Unable to find this Dll:
Windows\System\DDEML.DLL Try reinstalling the application.
This error comes not only when I load windows but also when I close any application or install or uninstall any application. Please tell me how can I get rid of this error.

It keep coming up all the times. Please help me out in this regard.Thank you