Quote - the bump map works for me, although my settings are slightly different than yours. Im still using Poser 7.0 - ive not installed sr1 yet also im on a mac if that makes any difference ?

YEs, any texture map attached to BOTH the Diffuse Channel node and then to the Bump Channel, weather direct connect like yours or via a math node will indeed reload upon re-opening your scene or re-loading the item from the library. But that is not exactly the way the Bump Channel was intended to be worked...but does cut down on file size - BUT, suppose your Bump map does not follow the grey scale conture of your color map? Suppose you are doing a high quality render and what to use the Bump channel for a specially prepaired bump map?

Also I have noticed that a Proceedural bump node will re-load fine too.

As for 'my system not caching' the maps correctly:
Well, it's not a matter of 'caching' them for this does not occure while actively working, it only occurs when the item is saved to the library or to a PZ3 and then later on Re-opened, at that time it should re-load the textures - All of them, Including the Bump Map (and also note: it is ONLY the Bump map that is effected - a "caching" issue should be random, a bad code would effect ONLY the node that is coded poorly ;p    kinda like adding 1+1 hu?