I have been experiencing the same problem trying to import load profiles.
Irrespective of the format I get the 'conversion errors in data in line 1' message every time.
The data I have is on a 20-minute interval. Beacuse such option is not available in PVSol, I reduce the number of values to17520 so that it fits to the 30-minute format.
I checked every other possible cause like format,number of values etc.
Files attached.
Please help
values.txt
load profile EAC789070.CSV