Is your path to the gta-vc.exe executable set correctly at Tools->Settings?
try the suggestion that posted here (http://forum.vc-mp.org/?topic=638.0)
I remember having this issue back in the days. What I used to do was, open my file explorer and type
%APPDATA% in the address bar and then hit the enter key. Then scroll down to the
VCMP folder and open it. After that I simply removed the
04beta folder that was inside it.
(https://forum.vc-mp.org/proxy.php?request=http%3A%2F%2Fs2.postimg.org%2F8v9lispmx%2FScreenshot_1.png&hash=e1e2de6246db81ac927255ab5c91f694074c96cd)
NOTE: If you're running the browser as admin then you'll find the
04beta folder inside
[OS-DRIVE]:\ProgramData\VCMP instead. That's because you're no longer under your regular user. Remove them both, just in case.