Hi greengreen,
the maxwell installer, a.k.a Maxwell_3.0.1.0, is an executable file. Therefore, to double-click it and run, it must have execute permissions for the current user. Try right-clicking on it and assigning execute permissions for user, group and other. I don't know the exact details on how this is done in the window manager of Ubuntu (i use Fedora), but it should be straightforward.
Regarding the .tar.gz file, it creates a folder called maxwell64-3.0 with all the maxwell files inside. The only thing left to do (this is done by the installer) is to create a couple of environment variables in your $HOME/.bash_profile called MAXWELL3_ROOT and MAXWELL3_MATERIALS_DATABASE
MAXWELL3_ROOT points to the folder where maxwell is installed, so for example, if the .tar.gz was untarred in /opt/local, MAXWELL3_ROOT would be /opt/local/maxwell64-3.0/ (note the final slash)
Following with this example, MAXWELL3_MATERIALS_DATABASE would be /opt/local/maxwell64-3.0/materials database/mxm files/
If you use bash, add these two lines in $HOME/.bash_profile:
Code: Select allexport MAXWELL3_ROOT=/opt/local/maxwell64-3.0/
export MAXWELL3_MATERIALS_DATABASE="/opt/local/maxwell64-3.0/materials database/mxm files/"
If, instead of using bash you use csh, edit $HOME/.cshrc and add these two lines:
Code: Select allsetenv MAXWELL3_ROOT /opt/local/maxwell64-3.0/
setenv MAXWELL3_MATERIALS_DATABASE "/opt/local/maxwell64-3.0/materials database/mxm files/"
Hope this helps.
Miguel.