I too had problems with using the Spreadsheet API in MAMP. To be more specific, I had hangups in the Google Data API because it couldn't validate a URL request. All I did was just use another php package and the hangup was gone.
What exactly is this bug in 5.3 that you speak of? I ask because I'm running the command-line Spreadsheet demo and it calls the getListFeed() function without any hangup and I am using php 5.3. -Vahan
