I've seen it happening at times with version 8, both because of broken downloads, and also differences in the binary files when downloaded from different service pack levels.
Another quick and dirty solution, if the number of ESXi hosts is not that much, is to directly install the vib files into the hosts… I know it's not a good solution, but has saved me some hours of work once to try and find out why the import or the deploy stage was not working as expected. To be honest, both those errors were happening on the v8, in v9 I never had problems while preparing ESXi servers….
Luca.