Unable to compile the theme...

Description

You get the error message Unable to compile the theme "..." in the theme configuration.

Cause

Here there are two possibilities at present, because this error can result from an unknown variable in a configuration field or from a wrongly filled configuration field. Both options are actually an incorrectly filled configuration field.

Solution

The crucial part is the part directly after the message Unable to compile the theme "...". It says either Undefined variable $... or parse error: failed at $....

Unable to compile the theme "...". Undefined variable $...

Undefined variable $...

Unable to compile the theme "...". parse error: failed at $...

Parse error: failed at $...