Import Data - Can`t select any system


I can`t continue with import process, because I can`t choose anything from drop-down list:

What I can do in this situation?
I already closed installed board (xenForo), tried "debug-mode" and looked in "Server Error Log" - there is nothing.

Thanks for your time.

Looks like all this case was caused by high restrictions of chmod.
For import, I applied chmod 777 to all files and directories, and, voila! Now I can select system to import from. :)

Later, I`ll make some tests about setting "read" ability to "/library/XenForo/Importer" directory.

Thanks for your feedback!