I've been getting this the last few beta's and just took a screenshot.
"error writing to file: c:\....\Libronix.DigitalLibrary.Resources.dll verify that you have access to that directory."

Clicking Retry brings up:
"Error writing to file: c:\...\Libronix.Utility.dll"

Interestingly enough, Logos did not automatically restart on this install either.
Install Log is attached. http://community.logos.com/cfs-file.ashx/__key/CommunityServer.Discussions.Components.Files/76/3750.Logos-Log-Files.zip