OK, that solved the problem of installing. Only a shame that I can't try this version because it says that my trialperiod expired. Apparently it "remembers" that I previously tried an earlier version. But I guess that's understandable...
Probably the message you got concerned installing the .NET Compact Framework. Please use the small installer (2.5 MB) that comes without the .NET Compact Framework. Since you already installed the framework last time you don't need to install it again.
If that doesn't help, please forward us the error message. Should be no problem to re-install the software.
A few weeks ago I tried an older demo of RunGPS. It worked fine on my HTC S710. Although I had plans for it, I didn't buy it yet. Now I found out that there's a new version, so I tried to install this one (after deleting the older demo). Unfortunately I can't install this new demo. Within a second I get the message: Can't install software (or something like that). Is this because I previously used an older demo or is this a sort of bug?? How can this be solved? I like to buy this software, but I must be sure that it functions correct...