iReport 5.1.0 is notorious for (Java 8 or higher). The Fix : You must have Java 7 (JDK 1.7) installed.
To download , you should primarily use the official Jaspersoft Community SourceForge repository, as iReport has been officially replaced by Jaspersoft Studio. Overview of iReport Designer 5.1.0 best download jaspersoft ireport designer 510
It is important to note that by Jaspersoft. In 2014, Jaspersoft announced that Jaspersoft Studio would replace iReport as the official design client. Why Switch to Jaspersoft Studio? iReport 5
Open iReport. Go to Window > Palette to ensure components load. Create a blank report and drag a "Static Text" field onto the designer. If it renders, you have successfully installed the best version. Overview of iReport Designer 5
The following direct links point to the official SourceForge CDN (as of this writing). Always verify the file name and size: