when I go to shared files the progress bar has turned red again and it seems as though amule is trying to redownload them again
You mean the indicator below the header "obtained parts"?
That does not mean that you are downloading the file again,
just that currently nobody is downloading this file from you (I think).
After a while, when somebody has been downloading that file from you,
some of that red will turn into blue.
BTW, its there where you can verify what the exact location of your downloaded files is.
Enable the "Directory Path" header by right clicking the column headers and opting for "directory path" option.
Then take a look at the path that is contained in the column for that specific file you are looking for.
Your disc is not full, is it?