Anybody know what I have done wrong ....on exporting audio of last tune I have been working on to microsoft wav what i get after a long time of downloading  is the song with a huge silence at the end which the player insists on playing ..silence that is  till the end of track untill it moves on to the next which is a bit of a drag .Help/advice  is needed please

By default SONAR stops playing or exporting when the last bit of data is encountered in the project. Projects which seem to play past the "end" of the project usually have automation nodes or MIDI past the "end" of the project.
 
Here is one solution to clean up the project http://forum.cakewalk.com/FindPost/3205757
 
Another is visual inspection of the automation data and looking in the Event view for MIDI data.
 
Alternately, specific the time range to export. This can be done after selecting the tracks to export, drag across the time time or use the Select From/Thru or By Time or add markers to the project and select the time range based on the markers.
 
This is a question about SONAR usage; moved from Problem Reports to SONAR.

Try importing the wave back into a new project and see if there is in fact a large amount of silence on the end of the track.

What may of happened is you have a node or piece of data way out of sight.  Do any of the tracks have a series of little dots after the "end" of the tune.  This would indicate the above. also select all show events list remove note data from the manager this will show any none note data and their timestamps.

Wookiee
Try importing the wave back into a new project and see if there is in fact a large amount of silence on the end of the track.

What may of happened is you have a node or piece of data way out of sight.  Do any of the tracks have a series of little dots after the "end" of the tune.  This would indicate the above. also select all show events list remove note data from the manager this will show any none note data and their timestamps.

Well, the exported wave with a lot of silence is going to import back with a lot of silence as well. On export the silence is encoded as gazillions of zero value samples. What you could do is import the wave with the long silence back into a new project, then cut/trim off the silent end of the actual audio, then re-export the remaining shortened wave. That way you do not have to search for hidden events in the track, because none of those are saved within the original overlong exported wave. That kludge will give you the exported wave without the silence at the end. If you want to use the wave in the original project though, it will still be necessary to find every possible event on all of the tracks beyond the time that you think the project should have ended. Otherwise if you import and shorten it, and then export it, you may get the same overlong result as Sonar tries to extend the duration of the wave to the duration of the project as it sees it.