This error is displayed when running the ETL tool outside the ETL_Tool/bin directory (which is usually the case when used in conjunction with a scheduler):

Exception in thread "main" java.lang.NoClassDefFoundError: largesoft/tools/etl/ETLTool

As described in the ETL help menu (available when invoking -help), the ETL_HOME variable in the ETL start up script must be available at the absolute path when using this parameter. By default, the ETL_HOME is set to "."; however, you must set this variable to an absolute directory path when running ETL outside the bin directory, for example, C:\dev\Reports\ETL_Tool.