For some reason, whenever I try to load certain items from my library.  I'm getting a "windows - no disk" error.  Is there a fix for this?

What items?  Is that the exact text of the error?  Hadn't seen that myself so far but it sounds ominously hardware-like.  

In any case I urge you to back up your data ASAP.

Assuming you are on Windows XP, try closing all applications and checking your hard disks' health:
Control Panel
Admistrative Tools
Computer Management
In the left pane, look for Storage/Disk Management
Left click Disk Management
In the top right pane, find the disk drive your Poser install lives on
The Status column should say "Healthy" (if it does not, you have a problem)
Right click your drive and pick Properties
On the Local Disk (C:) Properties applet that should appear, click the Tools tab
The top part of the Tools tab window should be Error-checking
Click the Check Now... button
A Check Disk Local Disk (C:) window should appear
In Check disk options, check first option Automatically fix file system errors
Click the Start button on the Check Disk window

That will take some time and will if it actually finds any disk errors, it will speak up; if you are using NTFS there is a good chance that any problems can be fixed.  If you are using FAT32, you may have less luck fixing things.  Also, your problem might be that your hard disk is having some mechanical problem that might not show up here.

Sounds like something wonky with your poser install. I'd try reinstalling Poser and see if that fixes it. I know when I get weird things going on with Poser, a quick reinstall of it usually fixes it.  Don't forget the SR updates afterward though :)

Seems like I've seen that when the path/paths in the file are incorrect.

likely to be poser is trying to access one of your disk drives (floppy, CD, SD etc) by default when you first open a file dialogue.