Yes, they changed quite a lot of things in J1.6 … all the global variables (from J1.0 that were supported in J1.5) no longer work in J1.6. While that fix you mentioned above will work, it’s not ideal in that if you upgrade Joomla to a newer version (e.g. version 1.6.4 when it comes out, which you should do for security reasons), that /administrator/index.php file might get overwritten, and you’d have to re-apply the fix every time.
Instead, modify the component that you installed, put that fix in the main component file. Or even better, create a custom Joomla plugin (system plugin), with those two lines inside it.
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