Go to LW's menu Tools>Options>Speed & tick Disable Ultrapeer Capabilities & press the Apply button. Go to Tools>Options>Uploads>Basic & reduce uploads to about 80%.

When you open LW, let it settle for up to 30 mins or more. Don't jump in & try to search before hand. Don't use the Resume/Find Sources button on many (if any files)! Otherwise this will give our LW connection quality problems.

Is that a USB modem you're using? If yes, & you have the option of ethernet & you have an ethernet card on your comp., use that. It's far more reliable than USB. USB modems get their power from the comp & utilise the cpu for operation. Whereas ethernet modems are independent (& faster.)

So what brand & model number of modem/router do you use?

Have you configured your firewalls to allow LW full access: http://www.limewire.com/english/content/firewalls.shtml