Losing connections

[Trogdor]

Hey, im having a problem running a OpenTTD server. Everything works fine more or less but people tend to lose connection. Here's a couple of the error messages i get.

"Client #?? is slow, try increasing net_frame_freq." - Increased it to 3.
"Client #?? was dropped because blah blah blah 4 game days."

Everything else is working fine and dandy.
Shouldn't be any problems with ports either, both are directed to my computer.
I currently have 384kbit upload, how many players is this sufficient for?

It might've been that i have had a unstable internet connection lately, but i dont know.

[Loony Locomotive]

Do you know what the clients' connection speed is?

I still live under the shadows of 56k Dial-up and I occasionally have a problem with losing my connection, even sometimes with net_frame_freq set to 125!