ok, i had this problem and i have been seeing this problem after a new installation of ispconfig when using the remote framing plugin.

i am able to create accounts automatically, but the ftp dont work

so if you are also expiriencing the same problem i have the solution for you

i posted this here because i keep asking the same question,

you can find the fix in this post:

http://www.wallpaperama.com/forums/ispconfig-ftp-login-problem-cannot-log-in-ftp-error-530-login-incorrect-t5680.html