OK, I remembered that the offending effect was the fx_dummy.fx. You can find this file in the Effects folder. I would suggest you back it up, then open it with notepad and replace the text inside with the following and save it:
[Library Effect]
Lifetime=5
Version=2.00
Radius=0
Priority=0
[Properties]
Spot=1
Tower=1
[Emitter.0]
Lifetime=0.01, 0.01
Delay=0.00, 0.00
Bounce=0.00
Rate=1.00, 1.00
X Emitter Velocity=0.00, 0.00
Y Emitter Velocity=0.00, 0.00
Z Emitter Velocity=0.00, 0.00
Drag=0.00, 0.00
X Particle Velocity=0.00, 0.00
Y Particle Velocity=0.00, 0.00
Z Particle Velocity=0.00, 0.00
X Rotation=0.00, 0.00
Y Rotation=0.00, 0.00
Z Rotation=0.00, 0.00
X Offset=0.00, 0.00
Y Offset=0.00, 0.00
Z Offset=0.00, 0.00
Pitch=0.00, 0.00
Bank=0.00, 0.00
Heading=0.00, 0.00
[Particle.0]
Lifetime=0.01, 0.01
Type=19
X Scale=0.01, 0.01
Y Scale=0.01, 0.01
Z Scale=0.00, 0.00
X Scale Rate=0.00, 0.00
Y Scale Rate=0.00, 0.00
Z Scale Rate=0.00, 0.00
Drag=0.00, 0.00
Color Rate=0.30, 0.60
X Offset=0.00, 0.00
Y Offset=0.00, 0.00
Z Offset=0.00, 0.00
Fade In=0.30, 0.30
Fade Out=0.71, 0.71
Rotation=0.00, 0.00
Ground Normal=1
Face=0, 0, 0
[ParticleAttributes.0]
Blend Mode=1
Texture=fx_aurora.bmp
Bounce=0.00
Color Start=255, 255, 255, 1
Color End=255, 255, 255, 255
Jitter Distance=0.00
Jitter Time=0.00
uv1=0.00, 0.00
uv2=1.00, 1.00
X Scale Goal=0.00
Y Scale Goal=0.00
Z Scale Goal=0.00
Extrude Length=0.00
Extrude Pitch Max=0.00
Extrude Heading Max=0.00
Let me know if it works (<- Do not paste this in the file

).