FAQ:How to provide a makehuman log for a good bug report?
When you run MakeHuman, four (two if you are on Linux) files are created into your home/makehuman directory (see FAQ:Where are my MakeHuman files found (where is my HOME directory)?)
If a crash has occurred, the makehuman.log file is usually the most interesting, but it doesn't hurt to include all of them.
As alternative (and if the bug doesn't prevent the start of the GUI) you can also look in "Utilities"-->"Logs". Select the error and use the button "Copy to clipboard" in order to paste it in the report message.