Created attachment 259 [details]
zip of 3 different xml files: bug, fix (more like a work-around) and problem.
By making constructor integers non-const the rate and then also the costs are obtaining ridiculous values (-1, -1073741823) eventually resulting in the crash of server.exe
Observe two files in the attachment, bug.xml which has a int predecessor constructor, fix.xml which has made this a const.
This disables some possibilities for constructing a schedule (such as problem.xml in the attachment, you can't change to a const int there)