We've received several enquiries about ViewRanger's support for the Nokia 6600, because it isn't listed in the supported phones at http://www.viewranger.com/phonesupport.php.
The maps and GPS link in ViewRanger work without problems on the Nokia 6600. We have a number of customers using ViewRanger on the 6600. We test new versions of ViewRanger on the 6600 and will continue doing so.
The reason the 6600 is not listed as supported is because it has a very small memory - just 3Mb for applications to use when they are running. This means that 3D panoramas are very limited on the 6600 and you can't increase their visible distance much above 10km.
The maps and GPS link only require a small amount of memory so work fine on the 6600. If you are recording a track you need to avoid recording too many points, so in Options > Settings > Track keep the distance and time between samples as high as you can.