I'm having the same problem.
1 First, I installed bitnami-RubyStack-2.0.0-20-windows-installer (OK)
2 Second, I installed bitnami-redmine-2.5.2-2-module-windows-installer (OK)
3 Third, I installed bitnami-Testlink-1.9.12-0-module-windows-installer (OK)
Finally installed obitnami-mantis-1.2.17-2-module-windows-installer (Error)
"The requested URL was not found /mantis/admin/install.php on this server."
during installation no error occurred. And already redid the process and the error persists.
I thank you.