You're calling mouse.tga in the EQUI_Animations.xml file...
Code:
<!-- Cursors -->
<!-- SOLARIA -->
<Ui2DAnimation item="A_DefaultCursor">
<Cycle>true</Cycle>
<Frames>
<Texture>mouse.tga</Texture>
<Location>
<X>0</X>
<Y>0</Y>
I just replaced this with the code from the default skin, and I have a mouse cursor now.