problems loading themes

I moved a wordpress site from .com to org, now im having problems installing themes.
This is the message:
Downloading install package from https://downloads.www.ads-software.com/theme/clean-retina.2.0.1.zip…
Unpacking the package…
Could not create directory.

This problem seriously needs to be corrected as its for a client and she does not want to be troubled with FTP. Does anyone have any suggestions ?