mac App Store will not let me update iMovie
I have a MacBook Pro 13in early 2011, Processor 2.3 GHz Intel Core i%, 4 GB 1333 MHz DDR3. I upgraded to Yosemite from Lion on Oct. 18 2014. No problems. I noticed a prompt from the App Store that an update for iMovie, ver.10.0.6 was was available on Oct. 26, 2014. I went to the Mac App Store, logging into my account with my one and only Apple ID and received this message: "This update is not available for this Apple ID, either because it was bought by a different user or the item was refunded or cancelled." I have been searching Apple support and the Apple communities since then to no avail. I currently have iMovie '11, version 9.0.9 on my laptop. Both iPhoto and ITunes updated properly after the Yosemite upgrade.I also get a message that says "All purchases have been downloaded for this account". I have gone to my purchase page and there is not option to "Accept" as has been suggested in the forums. I have gone to "My Account" page and clicked on the Reset button. However, it appears to be greyed out so nothing changed with that. I have logged off and logged back on repeatedly over the last few days. I have turned my laptop off and then back on. I want to Disk Utilities and followed the steps for Verifying Permissions. Both iPhoto and IMovie came built-in with this laptop, and it seems odd to me that iPhoto would update but not iMovie.
I don't know what other steps to take. Any advice would be appreciated.
I did change my password about 4 months ago, but that is the only change to the account that I have made. Everything else is unchanged.
MacBook Pro, Mac OS X (10.7.5)