Try changing Rendering systems GL/X to Direct3D9. Mine used to do this until I changed the rendering system.
Good luck! ^^
Usually, for me at least, the common cause of this is that there's something wrong in the material file. Aka, a part of it missing or a piece of coding in there that isn't supposed to be there. If you could post your material file here or through PM so I could take a look at it that'd be very helpful c: And also is there any effects you're trying to do on the preset such as transparency, glowing, scroll animation etc
You just use this:
[code@] Example text (You should put the material file text here) [/code@] (But without the '@')
And it should appear like this:
Example text (You should put the material file text here)
c: