Thanks. I have imported SPM12 and CAT12. This error message came up after installing CAT12 but it seems to have been installed successfully.
I used the default anatomy - ICBM152 - for my analysis. Is the correct next step to right-click MRI:ICBM152 > MRI segmentation > CAT12 and set number of vertices on the cortex surface to 15002? For cortex I have cortex_15002V.