That last transformation isn't needed. And with if and aif, you can get it down to two and one lines respectively.

But yes, it's one of Scheme's few failings. And it's one of the things that makes me consider switching to CL.

As much fighting as there is between them, they're not that dissimilar...

The second program will work in every Scheme I can think of (depending on what you want returned when the condition fails, but it shouldn't crash). I don't know what T did differently, but it's no longer the case.