>> "I was not able to find any example for this one and the samples & online tutorials provided cannot clarify my problem."
The C example is a good place to start: http://wyday.com/limelm/help/using-turboactivate-with-c-plus-plus/
It shows how to use the API and where to put the TurboActivate.dat file (in the same folder as the executable).
>> "1. I up to now chose to set the path for the dat file in some test folder. So when my activation method is called i load the .dat file from there. PDetsFromPath returns TA_OK."
If you've renamed the TurboActivate.dat to something else, or you've moved it to a folder that is not the same as the executable's folder, then you need to call PDetsFromPath() once (and only once) before you call any other TurboActivate function.
>> "Why is it that although the file is loaded, all functions i have tried return this error?"
Because you didn't actually load it correctly. You need to check error codes.
>> "Also, is the TrialDaysRemaining(..) using only the dat file, and that is why not other errors are produced?"
I don't know what you're asking.