This error generally occurs in UNIX because the environment variable DB2INSTANCE is not set and exported before the Easysoft ODBC-ODBC Bridge Server is started. You need to either:
DB2INSTANCE=xyz export DB2INSTANCE
before the cd
at the end of the file
-Or
Alternatively, if you are using the unixODBC driver manager, you can use SQL_ATTR_UNIXODBC_ENVATTR
in the odbc.ini file to set environment variables per DSN.