iphone simulator shows blank screen

When I run iPhone simulator (SDK 3.1.3, MacOS 10.5.7) standalone or from XCode - I s开发者_运维技巧ee only black screen. In the console I see a lot of:

"invalid pixel format"
"invalid context"

Any ideas what happens?

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I don't know if 3.1.4 is a typo and you mean 3.1.3 or not, but the latest iPhone SDK is only supported on Mac OS X 10.6 Snow Leopard.

Probably explains why it doesn't work on 10.5 Leopard.