Actually, it's best to install both expansions on the original game, and then install Equilibris.

Installing one of the expansions (Whirlwinds/Storm) before Equilibris is sufficient. At least, I only have Whirlwinds installed, and Equilibris works fine on top of it.
For example, I've never even seen Storm. I have licensed copies of both Whirlwinds and Storm, but the game itself is a pirated copy, and Storm won't install on it.
Although, the game itself was originally a licensed copy, but one day the game disc... shattered into pieces right in the drive:D I bought an identical disc (it took me a whole year to find it!) - it's a pirated copy (I even compared the installation discs - they only differ slightly in color, and the licensed version has the StarForce logo), and I couldn't install Whirlwinds on it - I had to find a pirated version of Whirlwinds :( That's a sad story...

P.S. Sorry for the off-topic, but I really wanted to tell this story:o