1013 - Unexpected character '%c' in variable name.

Description
Following a variable declaration character (.) an unsupported or unexpected character was encountered. Valid characters for variable names are A-Z, a-z and 0-9.
Example
Config:
.#MyVar = 'X'
Output:
c:\Test\fbuild.bff(1):(2) FASTBuild Error #1013 - Unexpected character '#' in variable name. .#MyVar = 'X' ^ \--here
Fix:
.MyVar = 'X'