Time Machine Backing Up Most Current Files

[olypenrod]

I recently moved and disassembled / reassembled my network. I want to upgrade from OSx 10.5.8 to Snow Leopard and then to Lion and need to re-establish my backups before doing so in the event of a failure; but I cannot get Time Machine to backup any current files - only the earlier ones. I've removed my Maxtor 1TV drive from the network and hard-connected directly to the laptop USB port, I've poked and prodded every Time Machine preference option and Time Machine is both recognized by the computer and goes through the backup; but fails to update the current files. I have also scoured MaRumors and Google to no avail for a solution. It is now beyond my expertise level so someone with a broader Mac experience please share your solution. Thanks.