All tables used in a form must exist at the time that the form is compiled, so that the compiler can verify the data types of the columns. The indicated table does not exist in the database that is named in the form. Check the spelling of the table name and database name. If they are as you intended, either you are not using the version of the database that you expected (check the value in the DBPATH environment variable), or the database has been changed.
The tables that are specified in the TABLES section of the form exist, but column-name, which is named in the ATTRIBUTES section, does not. Check its spelling against the actual table. Possibly the table was altered, or the column was renamed. You can use IBM Informix SQL to check column names under the Tables menu, Info selection.