If this error message appear, I couldn't close it.
If I click "OK", message box disappears and appears again.
Not only previewing, The error which include "-108".
(saving, opening and ETC....)
How do I close this error message box?
Which version of Illustrator are you using?
Also, are you working with very complex documents?
Win 7, CS6(64bit)
and It just very simple document.