Juan - just to add my two cents, I am having the same issue with repeated requests to download and install updates. I reset the ACL permissions in the Home folder (and fixed permissions globally) however I still receive the repeated requests to download and install the updates (as well as the fairly routine crashes upon exiting the application). Out of curiosity, I did a screen capture of the modules to be downloaded/updated, and then compared that against what is currently installed in v1.8. Well, it seems they HAVE all installed and updated just fine - that is, the listed versions in "Manage Modules" matches those shown in the "Available Downloads" - but the requests continue. At least at this point it seems I can confidentially just hit "cancel" when asked to update these same items.
John