IDL 8.1 is known to have some problems when installed on Lion (and possibly some installs of Snow Leopard). This is a known issue that has to do with some of the libraries distributed with IDL (specifically libcurl).

Symptoms

On a fresh, new install of IDL 8.1 on any version of Lion, starting the binary causes crashes, almost immediately on start. It is totally unrelated to any licensing problem and will crash even if a dialog box is present on the screen.
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