A few users have been reporting problems importing ringtones from AudioExplorer+, getting an “Unable to Download Ringtone” error message like the one below:

So far I haven’t been able to find out the problem here. Setting the iPhone in safe mode (i.e. with the SBSettings tweak, which is available for free in Cydia, as in this video: http://www.youtube.com/watch?v=FoSWAdfvmYQ. Note: Please place items in AudioExplorer+’s queue before entering safe mode) doesn’t always to help. If you’re having this problem, please look at the iOS log file when importing the ringtone (see this link to find out how to read the log file: http://superuser.com/questions/15855/iphone-log-reader) to see if anything is logged there from AudioExplorer+ that might pinpoint the problem.
I myself haven’t had this problem with ringtones (just occasionally with iTunes imports) and I think for most users both imports work fine.
Ringtones require conversion to AAC/m4r before importing, the conversion is handled by Michael Tyson’s TPAACAudioConverter library. I doubt the library is the problem, but it’s worth looking into, as the code is a bit old and may have problems with newer versions of iOS. A good way to test this would be to import a file that is already in the AAC format (i.e. files with the following extensions: “m4a”, “m4b”, “m4p”, “m4v”, “3gp”, “mp4”, “aac”) and see how the ringtone export works with that.
UPDATE: One user who was having this problem on iOS 6.1 solved it by “by updating to 6.1.2 and re jail breaking.”