Inkscape Wont Run On 10.4, Font Cache Error Message, Dissapears from Dock, No Suitable Image

This is due to a disparity between the version of X11 Compiled with Inkscape and the local version of X11. To fix this, you need to install the X11 update from Apple. http://support.apple.com/downloads/X11_Update_2006_1_1_3

If X11 is open, close it, install the update. Inkscape should run. If it doesnt, try a fresh uninstall reinstall.