Interesting. I think I used wifi on the first time and just mobile on the second time. And then, later enabled wifi on the 2nd, too. No difference there - it D/L'd everything nicely on the first time and totally blows on the 2nd - no matter what.
mkay, seems that the error could be related to the version of the market. I've got 3.4.6 now, but 3.5.15 seems to be needed to use the market correctly. Trying out now, will post back how it went.
Yup, that worked.
The final verdict: Google play won't allow you to access if it is outdated. That's where the error 101 comes from.
Got the new version from there