I don't know... there are still a number of things that could (but shouldn't) cause 256KB to be a problem... it could be disk space, memory issues etc... but those should show up in the error log.Is just a fixed number in the Module manager good enough? Is there really a reason that the users should change this?
After that it's some kind of a limitation on the network (maybe a firewall rule is getting triggered or something). Remember it's the HTTP web server making an outgoing request to another web server for data. When you are using CMSMS on a remote host this is not a problem with the desktop machine or your home network. That only applies when the CMSMS install is ON your local network.
The returned data can be fairly large. If you have this problem consistently then you will have to try to provide information as to what is causing it. There is an error message someplace (maybe on the server, maybe in your network logs...) or with your host.
I repeat I have no problems getting any of these modules on my stock ubuntu setup, ... or even with any of my remote test sites (on linode servers).
