Emissive bitmap always gone missing after restart

[jackwu10]

hey guys.. i keep on having trouble..
for example, a shop front, i have a jpg texture, for diffuse bitmap, and i use same jpg for emissive, cos i want it to look bright.
it works, but everytime i restart a sketchup, let say, 10 shop fronts, 2 of them will recognise the emissive bitmap, but rest 8 dont, i always need to go back and reapply the emissive bitmap.. it's very frustrating..

i am using su8 and vray 1.49.01.

pls can anyone help?