[RUNGSI]

It means that the texture is not supported.
The format is incorrect.

I have psted this info before to people and its probalbly the same thing.
Like Slyk said
Are you using the rubble texture, I believe its loacted in Birlin textures from spearhead.
Its the 1 with wood, and concrete all broken up.
That texture for some reason is bad.
I made a new version of the texture, its in my Thunder 2 maps pk3 file
named cockburn.