After downloading the "MinecraftDev.dmg" file (for snapshot 13w17a) on my Macintosh computer, I attempted logging in to the new launcher by pressing the "play" button. All seemed to go well, with the starting code scrolling down the screen... Until it stalls and displays this message in the left-interface:

Client> 249 recipes
Client> 27 achievements
Client> 2013-04-27 20:13:36 [CLIENT] [INFO] Setting user: mime2227
Client> 2013-04-27 20:13:36 [CLIENT] [INFO] (Session ID is -5903642868000586824)
Client> Invalid memory access of location 0x0 rip=0x0
Client>
Game ended with bad state (exit code 139)

[It then displays the message "The application Minecraft quit unexpectedly" after closing the application]
I have looked it up on YouTube, but cannot yet find anything relating to this serious problem. All I have seen are examples of players testing the new version with success getting to the main menu. I do have suspicion that this has something to do with my account.