As ahayes says, I think we need a few more clues.
If you have no source for the application concerned, the chances are you are stuck. Email the authors, rewrite the application, or find an alternative application that does work properly!
One glimmer of hope, though. Cut&paste buffers can supply data in multiple formats. It is just conceivable that the application you are trying to put the "paste" into is just not quite happy with exactly how you did the "cut". Some apps will have "Paste special" as well, which might help
, and might not
.