Really basic installation question

[Jack Orenstein]

My goal is to install IMP 3.0, so I'm installing Horde 2.0. I've got
Apache 3.19 and PHP 4.1 (the horde2 rpm), and I'm now stuck trying to
install mod_php. 

I have mod_php4-4.0.6-4.i386.rpm but I can't install it because it
requires libimap.so.4. Where can I find this library? I'm finding it
surprisingly difficult to locate a copy.

I have these:

    /usr/lib/libimap.so
    /usr/lib/libimap.so.0
    /usr/lib/libimap.so.0.0.0

which came with UW IMAP (I think), but I cannot locate libimap.so.4. 

Anyone know where to find this? Or a version of the mod_php rpm which
includes the library?

I know this isn't a horde-specific question, (I'll have those later,
I'm sure), but someone on this list must have been down this path.

Jack Orenstein