wombiroller, nice to see that you solved that problem
jimmejames, try to refresh the package list:
from command line or via Application Manager (there is an option refresh package list).
Before and after trying the code mentioned previously, I ran apt-get update and then again just now. I still get the 404s or the downloading failed errors. Maybe I don't have something correct. I got my n810 maybe 2 weeks ago and have a random assortment of things installed- few games, canola2, python, unzip, etc and I installed rootsh to gain root access.
To install LMCE, (this is all done on the n810) I open the x terminal, type in "sudo gainroot" and I'm taken to the /home/user directory. Here I type in, apt-get update (everything seems to go through with no errors) and then I type in "apt-get install lmce-orbiter-installer" and am told it will take up 15.9mb of space (I ran apt-get install lmce-orbiter-installer --fix-missing" and some things were installed, so that 15.9 is down from 17.something. Between the 404s and the size mismatches, it doesn't install.
Thanks for you help