[imp] PEAR not found problem

[Eric S. Johansson]

Fatal error: Failed opening required 'PEAR.php' 
(include_path='.:/php/includes:/usr/share/php') in 
/usr/share/php/HTML/IT_Error.php on line 20

I installed horde/imp at a client site on Red Hat 7.2 and had it all 
running nicely.  Then Red Hat upgraded PHP via up2date and now I'm getting 
the wonderful error seen above.  A google search turned up nothing.  Any 
pointers to FM TR would be welcome.

---eric