Hi,
To publish a form with code via the sandbox in SharePoint 2010, you'll need to have the Sandbox service activated in Central Admin, and you'll need to be a site collection admin. Step by step instructions for publishing qRules forms are available in the qRules user guide ( All Programs > Qdabra > qRules).
As far as the error:
1. Are you using qRules v4.1? If so, there is a new node called useWebServices (in the QdabraRules 2DS). If you make the value of this node TRUE, does the command work in the browser? You can temporarily display the node as a checkbox in the canvas, and check it before executing the command, as a test.
2. If other commands work, then it's not an issue with publishing, but rather an issue with the command itself.
Thanks for the additional info.