firefox not properly downloading files
i've been having a firefox problem for a while now, today i just updated from 1.0.3 to 1.0.4 and found it is still occuring: everytime i left-click on links of downloadable files, the "opening ..." window appears and lets me choose between saving the file to disk and opening it with a particular program. opening the file with a program then results in the download manager window popping up, downloading the file to /tmp and executing it properly. so far, so good. if i choose "save to disk" in the "opening ..." window, the download manager does not pop up, and i end up with a file of the right name, but with 0 bytes size in my downloads folder. when i right-click the link and select "save link as", the file is downloaded properly, too (that means i am able to download files, but not being able to do so by left clicking is plain annoying). any ideas to sort this out? googling did not give me any useful info yet.
various info: i'm on gentoo ~x86 (no, the error is not since i'm on unstable, it's been there before) firefox 1.0.4, gnome 2.10, athlon xp 1ghz, 512mb ram.
thanks in advance!