We are using AEM Forms 6.2 and the Designer that comes with it. Designer sets the template target version to Acrobat/Adobe Reader 10 at the lowest. Given that 10 is the lowest Acrobat/Adobe Reader version available why does AEM Forms 6.2 complain about exceeding Acrobat / Adobe Reader 8?
That error message (ALC-XTG-032-303) is generated by the XML Form service when you try to render a PDF Form where the render version is lower than the target version specified in the XDP at design time.
Check the Forms Workflow activity or the Java code you are using to ensure that you are specifying the correct target version when you are creating the form. It is likely the default version is lower than what is specified in the template (Acrobat/Reader 10)