Sonar puts a click at the end of exported audio what am I doing wrong?

When I have completed mixing my projects I mute and archive any unused tracks, select all the remaining tracks and select file-export-audio where I choose the 'what you hear' preset and export to 16 44.1k wav ( I should add that all the tracks have realtime fades at their begingings and ends so there are no 'non zero' points)

every thing exports ok but when I burn them to cd (using Pinnicle instand cd/dvd) there is a single large click in the silence at the end of the track (it's not the cd app cos i've also burned the wavs as data and used K3b and the clicks are still there).

I found a work around which is to reimport the exported tracks in to a new project, put new fades on the start and end of them, bounce to tracks and then grab them from the arrange page and drop them in a folder (bypassing the file-export route).

Thing is I don't want a work around I want it to work! I can hear no clicks when I play the mix back so why when I export 'what you hear' does sonar put clicks at the end of my tracks?

its an atholn xp 2600 rig 512meg asus a7v400x echo layla 20, works fine in all other respects apart from this one annoying 'feature' please someone tell me what I am doing wrong!?

edit: sorry forgot to say this is on Sonar 4.02SE

many thanks

Child