I'm using Windows here.  I followed the instructions and used the .jar instead, but got this error.

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Critical Failure

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Sorry, fatal error - please let Majalis know! An error.txt has been created in the game folder with the full details of the error. 

Error: OpenGL 2.0 or higher with the FBO extension is required. OpenGL version: 1.1.0

Type: OpenGL

Version: 1:1:0

Vendor: Microsoft Corporation

Renderer: GDI Generic

there is a bugs and errors thread and this might belong there. I had a similar problem a bit ago(different error), and all i did was uninstall and reinstall. If that doesnt work after a bit though, from what i see it seems your graphics card is too old or your graphics drivers may be out of date. Try updating drivers and if that doesnt work then maybe using a different device or getting a graphics card upgrade(doesnt have to be too new so it wont be crazy expensive).