User Permissions

I have a good amount of programing experience, but I am currently stuck on something:
I recently downloaded Joomla 7 and Wordpress 3.3 on my MacBook Pro (Running Snow Leopard) and want to develop them locally before I put them up.
With both programs, I encounter errors whenever they try to create a file path (for example, wordpress gives me an error when I trying uploading an image or uploading a them).
I have already give all of the necessary files the necessary permissions, and have scoured the internet for answers, but I still can't find an answer.
This is really driving me crazy because I have worked with wordpress locally before and have also created files paths of my own with php applications.
I haven't really done any programming recently, so I guess there might be something I'm missing, but I get the feeling there is something wrong with the global permissions on the operating system.

Any help would be greatly appreciated.

What permissions are you applying to each of the directories? It's very possible that there are simply incorrect permissions set.

Random thoughts...

-some applications require specific permissions on some platforms ie: .ssh won't work on some systems with 777 permissions, only 644 permissions on the authorized_keys and known_hosts files. Perhaps yours needs specific permissions: chmod

-some applications require installation by a specific user, or a user in a specific group. Perhaps yours needs to be owned by, or included in a specific group: chown chgrp

-some applications require links to their executable instead of just using the actual file. Perhaps you need a link in your home directory pointing to a file: ln

Thanks for the help!
I am currently giving 775 permission to the wp-includes file.
I'll look into some of the other suggestions too.

Have you read this?

Other research leads me to believe that the permissions on the wp-includes directory need to be set to 755, not 775.