Transformation to PDF fails (using Chemistry)

[eltopo71]

I have a bit of a problem with the standard "DITA Map PDF - based on HTML5 & CSS" transformation in Oxygen 21.1. I'd love to be able to use it because I know CSS a lot better than XSL-FO, but when I try to generate a document from a map using that transformation -- the standard transformation that comes with Oxygen and can't be edited -- I get this error:

System ID: C:\DITA_library\MASS Manual.bookmap
Scenario: DITA Map PDF - based on HTML5 & CSS
Input file: C:\DITA_library\MASS Manual.bookmap
Document type: DITA Map
Engine name: DITA-OT
Severity: fatal
Description: Transformation failed. C:\Program Files\Oxygen XML Editor 21\frameworks\dita\DITA-OT3.x\plugins\com.oxygenxml.pdf.css\build.xml:574: exec returned: 1

I'm quite sure I didn't randomly mess around with the build.xml file, so what could the issue be? I am using the built-in OT.

[Dan]

It looks like transformation is trying to start a chemistry executable that is not embedded into the oXygen installation. This may have two causes:
1. A corrupt chemistry installation is specified in the PATH environment variable.
2. An incorrect chemistry installation is specified in the transformation scenario parameter 'css.processor.path.chemistry'.
Please check the transformation scenario, making sure the parameter 'css.processor.path.chemistry' is cleared.

If the problem persists, please send us the full log of the transformation using: https://www.oxygenxml.com/techSupport.html.
You can activate the log from Options/Preferences/DITA/Logging/Show Console Output = Always.

Many regards,
Dan