Hello Nicolas14,
What recovery software are you trying to install? The file Rockey2.dll from what I can see is related to Microsoft Access Visual Database Tools Diagram Surface. If you are attempting to do an HP Factory Recovery and you are getting this error I would encourage you to post your product number for your computer. I am linking an HP Support document below that will show you how to find your product number. As well, if you could indicate which operating system you are using. And whether your operating system is 32-bit or 64-bit as with this and the product number we can provide you with accurate information.
How Do I Find My Model Number or Product Number?
http://h10025.www1.hp.com/ewfrf/wc/document?cc=us&lc=en&docname=c00033108
Which Windows operating system am I running?
http://windows.microsoft.com/en-CA/windows/which-operating-system
Is the Windows Version on My Computer 32-bit or 64-bit?
http://h10025.www1.hp.com/ewfrf/wc/document?cc=us&lc=en&docname=c02033168
Please re-post with the requested information and I would be happy to provide you with assistance. Thank you for posting on the HP Forums. Have a great day!