Just a quick FYI on this, Invision Power Board frowns on users redistributing the core installers without their express written permission. I have erased your download link for IPB2.0.0 as a result; next time we would be forced to take stronger measures.
I'm unfamiliar with installing IPB unfortunately so I can't do much else there to help, but I can confirm your account is currently set to utilize PHP 5.5.
Edit: Also worth noting that IPB 2.0.0 is 2 major revisions and a ton of minor revisions out of date; there's a good chance the error in question is being caused by PHP having made changes to how it operates since it is several versions (including 1 major) higher than it requires; if you're unable to resolve the error you may need to contact IPB for their help in repairing the error, assuming they still support that version.
Edit 2: After digging in further, IPB 2.0.0 is 14 years old, so getting help from IPB is probably out of the picture.