[Some Fat Guy in L.A.]

Was’t there a SF novel (or maybe a series) set on a planet called Pandora that was similar to Avatar? I vaguely remember reading it many years ago. By Harry Harrison, maybe?

[LibWhacker]

Is that the Poul Anderson short story the author refers to? Tried to download it but it's not available on the Kindle. Wouldn't mind laying my hands on Lem's story either. It sounds really weird, which is what sci fi ought to be imho.