How can they increase the karma so that avatars can be loaded without being disconnected by the server?

TIMP implements a leaky bucket algorithm. You can finetune two parameters: the duration and the size. Two backet allow to define a short period limit and a long period limit. By default
- Peak Bucket size id 10KB (10240) and Peak Bucket Size is 10 seconds
- Mean Bucket size id 20KB (20240) and Mean Bucket Size is 60 seconds

Start the TIMP console, double click on the TGService plugin, go to the custom part, and look for a line containing jpolld.exe. Add the following
parameters:
-pbs 1048576 -ps 60 -mbs 1048676 -ms 60

to set the limits, e.g., to 1MB of traffic every 60 seconds (both for paek and mean traffic).