When i launch radiant both from the stand-alone exe file or launcher i get a message

FATAL ERROR: couldn't load material '$default'
GetLastError() = 0
An unrecoverable error has occured. Would you like to edit Preferenced befor exiting Q3Radiant?

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Help i can't do shit 

asset manager doesn't seem to convert
yes the file format is dds.

it just says converted. press any key

this happened after i successfully installed bo guns (thunder gun and scavenger)