Rosetta is required to perform any export to .xls (Excel Workbook 95-2004) file in FileMaker Pro on an Intel-based Macintosh; it is not required for .xls export on PowerPC-based Macintoshes, or on Windows.
Rosetta is an optional install in Mac OS X 10.6 Snow Leopard, and not installed by default. It is installed by default in Mac OS X 10.5 Leopard, and in the appropriate versions of Mac OS X 10.4 Tiger. Upgrading from an earlier version of Mac OS X to Mac OS X 10.6 Snow Leopard may also remove existing Rosetta support. You probably saw an out-dated page on Apple's website.
Versions of FileMaker Pro prior to 10.3 will show Apple's dialog to install Rosetta, but then hang the application. FileMaker Pro 10.3 and later prevents the hang, but puts up the "missing component" alert before Apple's dialog to install Rosetta can be shown.
To install Rosetta, re-run the Snow Leopard installer (either on the retail Snow Leopard discs, or the system discs that came with your Mac) and select it as a Custom install option without installing anything else.
If there is no urgent need to continue to export to .xls, consider switching to the .xlsx (Excel Workbook 2007/2008) format.
Thanks for that... problem solved.
Being fairly new to the world of mac, I had no idea what rosetta was, so tried a quick search and got those listed above.
I guess it is still a bug then, even if it is something they know about, especially if previously it showed the dialog, then crashed..
A fix does not mean, remove the prompt altogether and show some confusing message (which they acknowledge as confusing) that is a temporary work around.
I do agree, switching to .xlsx is the better option here, however before I can do this I have to ensure I am not going to cause additional problems / compatibility issues for my clients.