Hi Albert!
I tried to calculate some routes in Costa Rica, and everything went fine! (using custom markers as you did).
I also use address search to look for the „Airport, Costarica“, and it find’s it without problems.
Maybe you did this when you were not online??? Please note: PE is completely offline EXCEPT route calculation (since this is done on the MapQuest Open server). (there where a lot of requests to do this off-line, but it seems to be a big developpement effort that Geomagik could not invest up to now).
=> So, if my assumption is right: go to the next WLAN, calculate all possible routes, save them, and happy travel for the next days!!!
Cheers, nounours.