Unable To Use Custom Permalink Structures — 404 Error Occurs

Hello. I have asked this question twice before, and have yet to receive a response, so I’ll try again.

I would like to use the WP Super Cache plug-in. However, the problem is that an on-screen message states that it requires that I use a custom permalink structure.

On several occasions, I have tried using some of the available custom permalink structures in the “Permalink Settings” window. However, each time that I choose any one of them, other than the default setting, whenever I click on a category link, or on a recent post link in my sidebar, my server throws me a 404 error.

Does anyone know what would cause this to happen?

Would it have anything to do with the fact that I have to use the “Disable Canonical URL Redirection” plugin in order for my blog to function properly?

Any feedback would be much appreciated.

Thanks!