Hi, I'm having difficulty accessing my Aperture library, with around 100GB of images in it. The details are as follows:

I had to back everything up as my iMac had a faulty hard drive (according to Apple - in hindsight, I wish I had not bothered to get it changed!). I back everything up to a cloud server anyway, but took the precaution of backing up a second time to an external HDD before sending the iMac off. So I got the new hard drive installed, and the cloud server has been reinstating my files. Trouble is, when I try to access them I get the message 'There was an error opening the database for the library…'.

I can't get to the repair menu (pressing the command and option keys together doesn't seem to work). So I tried to access the library from the external HDD - and got a different error message 'The library cannot be loaded because it is from a newer version of Aperture'. (which makes no sense).

Is there anything I can do? I had reinstalled Aperture (3) once I got the iMac back, and after the first lot of error messages I updated the software to the latest version (I think).

I really hope someone can help me with this, as I'm starting to get slightly nervous about it all and whether I can get my images back. The library on the external HDD is the right size so the pictures are presumably there. Thanks in advance.