On certain servers I get the MAX_PACKET_USERCMDS message frequently along with long connection interuptions. Also, no matter what server I join (except mine) I start off with a roughly 10 second conection interuption. Could someone plese explain why these two things are happening to me?

P.S.- My internet connection is one way cable

That is likely because your framerate is too high and the server cannot process all the updates that you send to it (a client update is issued once per frame). Lower your framerate cap by typing the following in console:

/seta com_maxfps [x]

where [x] is the desired framerate cap, in frames per second. I believe the default value for standard game is 85 which should actially work fine; but if you previously set it to 1000 or so (like JediMod's autoexec.cfg file does by default) then you might have problems because a fast system will actually achieve a maximum framerate of 200 or 500 at times. But it makes no sense to have it that high, the reason being that your display physically refreshes at no more than 160-200 times per second - all it does is eat up the CPU taking away resources from any background applications running, and cause connection clogging that you are experiencing. Find out what is the physical refresh rate of the monitor in the resolution that you play at (for instance, press the menu button on your monitor; vertical refresh rate (in Hz) should be displayed somewhere in the menus). Then set your com_maxfps value to exactly that number for smoothest gameplay, or, if that is not enough, to an integer quotient of that. For example, if your physical refresh rate is 160 Hz, set com_maxfps to either 160, 80, 53, 40, 32, 27, 23, or 20 (I consider below 20 fps unplayable for multiplayer).

I'm having the same problem on my own server, which runs JediMod 1.2...

Through rcon, the con_maxfps tells me it is set to 85, but I have been told that through a glitch in JediMod, its going to do this on bigger maps. Anyone know how to fix the jedimod glitch?

but in order to set a new default, you have to type

seta com_maxfps X the seta writes the command into the cfg file instead of just using the command that one time.

85 is default, I just typed the cvar to see the current setting... no proceeding variable.