Illegal characters in global prefix Explanation: The value specified for the /GLOBAL_PREFIX qualifier, or the file name if /GLOBAL_PREFIX was not specified, contains a character which is neither alphanumeric nor the underscore character. The converter will still operate, but the resulting code may not compile or link properly. User Action: Specify a value for /GLOBAL_PREFIX which contains only the upper or lowercase letters, the digits 0-9, or underscore ('_').