sudo cp -r flex_sdk_3 /Developer/SDKs/

i.e. there should not be any trailing slash on flex_sdk_3 (as this would not create the root folder, but copies all content below at the SDKs/* level.

An adidtional issue is the file permissions, that seemed to restrict all access to the owner i.e. root in this case. Not sure if it is a download issue, the auto unzip performed, etc. A hacky workaround to get going is to do:

sudo chmod -R ugo+rx flex_sdk_3

that will make all files readable/executable for all…

I’ve managed to compile my first flex apps

cheers!