Error code 500

[cdf6073]

Hello,

I have just tryed to install roundcube on my vps. And it says:
SERVICE CURRENTLY NOT AVAILABLE!
Error No. [500]

Please could you help me as I need webmail up.

Thanks

Cameron

PS I do not know what perfix to use so I use any

[SKaero]

Try removing the .htaccess file and see if it works, also check your RoundCube and Apache logs.