what does the flashing orange light on my ipod shuffle mean?

The flashing orange light means DO NOT DISCONNECT (eject shuffle before physically disconnecting). When flashing, the light has nothing to do with battery status.

If you eject the shuffle in iTunes (by clicking the eject button next to the shuffle's name in iTunes), the light becomes solid (not flashing). Solid light means OK TO DISCONNECT. Then, the light color indicates battery status.

If the light color is (solid) green before disconnecting, but the iPod does not play after disconnecting, and the shuffle's light does not come on at all when you move the power switch from OFF to ON position, the shuffle's battery is not holding its charge. That may be due to age (worn out battery). If the shuffle is less than one year from purchase date, it is under warranty.

In case the shuffle not playing is software-related, you can try doing a Restore in iTunes. The Restore button is on the shuffle's Summary (or Settings) screen in iTunes. This will erase the shuffle, reinstall its software, and set it default settings.

In the case of my 2nd gen Shuffle, when I tried to charge it it would blink three times orange and then stop, but never charge. Although I could not find this behavior documented in the user guide, I figured out it would not charge on some of my new PC's USB ports. I just tried different ports until I found one that worked. An alternate solution would be to get a Shuffle made this decade, but I like my old workhorse.

I like my old 2nd gen shuffle too... If the problem of not charging recurs, it may help to Enable disk use on the shuffle. This setting (a checkbox) is on the shuffle's settings screen in iTunes.

Some more recent PCs have a "energy saver" feature that turns OFF full power to the USB port when the connecter storage device (the iPod in this case) is not mounted by the system. By enabling disk use, iTunes keeps the iPod's "disk" mounted continuously (instead of only during syncing), which keeps the port at full power while the iPod is connected.

NOTE: With disk use enabled, you need to Eject the iPod in iTunes before physically disconnecting it.