Since iReport is now in maintenance mode, you can find the archived binaries on official community repositories: Official Archive: The most reliable source is the JasperReports SourceForge Archive
If you are attempting to run iReport 4.0.1 on modern hardware, be aware of the requirements of that era: jaspersoft ireport designer 4.0.1 download
iReports 4.0.1 not Launching - Products - Jaspersoft Community Since iReport is now in maintenance mode, you
Since iReport is now in maintenance mode, you can find the archived binaries on official community repositories: Official Archive: The most reliable source is the JasperReports SourceForge Archive
If you are attempting to run iReport 4.0.1 on modern hardware, be aware of the requirements of that era:
iReports 4.0.1 not Launching - Products - Jaspersoft Community