PERCH's NMR Software Tools are designed to run under Windows XP and Windows 7. In general the use of Windows 7 should be preferred over Vista.
Linux is not supported (yet) but you can use cross-platform virtualization software like VirtualBox to install and run PERCH in native Windows under Linux.
The installation package is about 150MB and the complete installation takes about 250MB disk space. Memory requirements depend largely on the kind of structures handled. Typical memory usage is between 50-100 MB but can be considerably higher for larger systems.
When encountering memory allocation faults it is recommended to increase the virtual memory used by Windows first. If this helps increasing RAM is recommended to speed up operation.