Karnataka Professional Tax

1) I have NO employees. So I am not an employer. But I am the sole proprietor for my biz. Am I liable to pay Karnataka Professional Tax? 

= Employer (corporates, partnership firms, sole proprietorship etc) also being a person carrying on trade/profession is also required to pay professional tax on his trade/profession again subject to the monetary threshold if any provided by respective State's legislation

2) I still have not registered for KPT thru e-Prerana. But paid KPT via  vat.kar.nic.in  filling my GSTIN number. I got a CTD reference number for successful payment. Is it ok or should I file returns in e-Prerana even if I have no employees? Please advise. 

= You should and must register for state professional tax and file NIL Returns and pay the yearly charges as applicable otherwise you may also be penalized as per you state laws and regulations