You backed up your Quicken 2000 on Microsoft Windows 98 second edition and tried to restore it to the new Quicken 2010 Deluxe on Microsoft Windows XP. Quicken 2005 was installed on that Microsoft Windows XP computer and you removed that software. Quicken version 2010 shows QDATA BACKUP-1.1.06QDF.
An ERROR message appears saying Authentication of convert-stub.dll failed because it could not find taht required file. Please reinstall Quicken to convert your data file. Reinstalling does not help.
Now what do you do, you ask? You can first try to update your version of Quicken 2010. Go to the Help menu in Quicken and have that program download and install any updates.
Also, you might need to perform some file cleanup duties ie. delete duplicates in memorized transaction list if that is necessary. Another option would be to remove Quicken 2010 Deluxe and then reinstall your version of Quicken 2005 if possible. Then try to convert that backup data into a Quicken 2005 version.
If successful you would then create another backup using Quicken 2005. Obviously you would save that backup and reinstall Quicken 2010 deluxe and try to restore that backup data from a Quicken 2005 backup file. You can try to make sure all files of your old data set QDF, QEL, QPH, etc. are copied to that folder where your Quicken installation expects final files to become located.
Then double click on that .qdf file. Quicken should launch and offer to convert that data. You could also download an intermediate trial copy of Quicken in order to just convert a backup that will be recognized by Quicken 2010.
I found trial versions for Quicken 2001, Quicken 2002, and Quicken 2008 via some of the following links. Quicken allows downloads of older trials for this purpose. Quicken 1999, Quicken 2000 and Quicken 2003 trials
Quicken 2008 trials are no longer available for download. If you must you might find a used copy for sale on Amazon and or eBay.