whenever I try to download any file, it'll finish downloading and then a message will pop up saying that it may be dangerous to my computer and so limewire has canceled the download. the problem is that it does this for every single file I try to download! How do I stop it from doing this?

I am guessing you are using the latest LW version. This is because LW now has a special filter that knows the hash design of known spam files. It knows these files to be fake files & removes the file at completion of downloading. I believe they will work on trying to have this action happen earlier rather than at the end. LW has added this filter to prevent people sharing these spam files (frequently viruses.)

But it suggests all your chosen files were spam.

How to find music and Virus thread: Typical virus spam file sizes - Make a note of them (click on blue link to see)

Is there any way for me to get it to let me download it even if it thinks it's spam?

no .. and it knows it's spam. Not just thinks it's spam. These are very common spam file hash designs that it detects ... it will not filter out all spam. Would you prefer to download a file pretending to be a music file but is really a virus?

It might seem annoying .. but the filter is there for a good reason ... to help prevent prolification & accidental sharing of spam viruses, as well as protect the downloader.

Perhaps you might be connected near or directly with too many spammers; http://www.gnutellaforums.com/345936-post2.html is one way to find fresh ultrapeers.