Scripts in WinCC!!

Hello,Im a student and in my project Im working on WinCC flexible 2005....but i have a problem...i wrote a script using visual basic to calculate el RMS voltage from a record of instantaneous readings...and made an internal tag for the Vrms and made an I/O field for this internal tag but when using runtime only el instantaneous voltage is read but the Vrms always equals zero....and attached my visual basic script...could anyone please help me with this problem...
Thanks...

Sometimes when the scripts are not working they will run to the line that is giving trouble then end. I would goto the bottom of the script and set the Vrms value to a odd number like 1234. Then run the script and see if I get 1234 on the output. Then keep moving the 1234 value up in the script to determine where the script is stopping. I bet your not getting the data out of the database.