If the problem occurs on just one track, then you will probably need to purchase that track from “blablabl;a.com”.
If the problem occurs on all tracks, then you may have a fake version of Audacity. The correct (official) place to get Audacity from is here: http://audacityteam.org/download/
If the problem occurs on all tracks and you have the genuine Audacity program, then perhaps it is a trial version of a plug-in that is producing the message, in which case you would need to either remove that plug-in from your system or buy it.