Synaptic "Some of the packages could not be retrieved from the server(s). . ."

[Jimbo]

For some time now I've been consistently getting strange behaviour when I try to install or upgrade programs in Synaptic.  Whenever there is more than one file to be downloaded (which is most of the time) it downloads all but the last file (as in, completes downloading file 159 of 160), then gives this message:
"Some of the packages could not be retrieved from the server(s).
Do you want to continue, ignoring these packages?"
When I press "No", it vanishes.  Then I immediately restart it, select whatever I had just selected, it downloads the last file perfectly ("downloading file 160 of 160" or 4 of 4 or whatever), and installs or upgrades normally.
When I go through and carefully select several programs that I want to install, then ten or fifteen minutes later have to go through and select them all again, it's a pain.
Any ideas?

[menotu]

Unsure if this will help but pinoc posted the following some of which relates to the sources.listt file


http://www.pclinuxos.com/forum/index.php/topic,87378.msg722604.html#msg722604

[taffykid]

Many thanks menotu  for the link and pinoc for the ' how to '  .i had same problem as Jimbo and was getting close to going bonkers .
   system now running like a dream cheers .