After configuring JMS Multisites (I also purchased and installed the menu and content extensions of JMS), my master site turns up 404 errors when one clicks on articles in the blog. I read somewhere and have seen posts about compatibility issues with SEF urls and was wondering whether this was a problem that I am also experiencing.

I should add that I use the native SEF url feature and also mod_rewrite with .htaccess. I also have a component called ReDJ that helps with redirects.

404 means that a page is not found.
I suspect that ReDJ modify the information of your SEF and could be at the origin of your problem.
Try disable the ReDJ.

JMS perfectly works with natif SEF as you can see with "jms2win.com" that is a slave site and that use the native SEF.

I have run ReDJ for close to a year now without any problems.
The only recent change is using JMS Multisite, so the question remains: What would affect this in JMS?

Give a detailled scenario to reproduce it.

We tried to install ReDJ on a master website and create a redirect URL and it does not redirect pages.
So before to blame JMS, you should explain us how to configure and make ReDJ working.
We have create an item www.master.com/index.php to redirect to jms2win.com and it does not work.
So how to make this ReDJ component working.
After that we could investigate why you have a 404.

I did not expect your defensive attitude. I am not attacking your precious component. But, it stands to reason that, if I have been using ReDJ for a year without problems, this component is not the cause of the issues I am experiencing.

It is not ReDJ that is currently failing to function. It is the simple blog article links that are not functioning anymore. Since the only thing I've changed in my site is the multisites (with its various patches), I think it is reasonable to ask whether these patches or something associated with JMS Multisites could be causing my problems. I do not know what's causing my problems ... perhaps it has nothing to do with your components, but I would have expected more than a defense of your components and pointing the finger at something else without looking into it.

I've the same problem. Everything is working nicely on the master site, when I copy it to a slave, then all links lead to 404 error.
I do not have a .htaccess, but just Joomla 1.7 regular SEF option selected.
Help appreciated