"make modules_install" hosed in 2.6.5-7.75 kernel?

I got the new 2.6.5-7.75 rpms for the kernel-default, kernel-source, and kernel-syms. They installed fine, and work fine. But I wanted to compile my custom kernel that I have been using but using this new source code. "make all" built the kernel and modules fine. "make install" installed the kernel and made the initial ramdisk fine. But "make modules_install" ran very quickly, didn't install any modules at all (although it did make the new directory and the "build" link, and then output only a "depmod -ae" line. Something appears to be broken.