It sounds like you are unable to export an email from your AOL inbox page in Safari all of a sudden. I recommend troubleshooting Safari for issues with any possible 3rd party plug ins that may be installed with this article:
Safari: Unsupported third-party add-ons may cause Safari to unexpectedly quit or have performance issues
If the issue persists, I would next try resetting Safari with this article:
Safari 6 (OS X Mountain Lion): Reset Safari
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