i fixed my time capsule mounting issue
i'm not saying this is the answer to everyone's time capsule problems, but...the situation started when i changed my network name and suddenly my time capsule wasn't mounting.
i plugged it in directly with an ethernet cord to my computer**(see below), I also turned off the airport in the menubar. initially, when i clicked to "backup now" (under time machine in menubar) it would give an error. after much to-do, i read one person's advice to just select "change disk" in the time machine system preference and reselect the time capsule (time machine should show up as a disk connected to your computer, if it isn't, try unplugging time capsule from the wall and restarting computer and see if it shows up when you plug back in and restart).
i clicked the "change disk" button and selected my time capsule and it was FIXED and i was able to backup as usual again! to think i almost wiped out my time capsule to start over and would have erased months of backups over this! so easy...

D with

again)
be patient, it might have to spend some time validating the disk. I quit all my applications and gave time machine the full use of my computer for as long as it needed to reorient the computer to the time capsule, it took an hour or so...but it had been over a month since the last backup. i'm SO HAPPY it worked!!!!
**as I'm sure you know it takes forever to backup over airport--sucks all my bandwidth to where I can't surf net or get mail sometimes, and I have aLOT of bandwidth supposedly, so i back up when I'm not on computer or over ethernet cord, otherwise time machine is off--check versiontracker.com for time machine scheduler software that will allow for you to schedule your backups at specific points during the day.