Technote Details :: Invalid Expression in Transaction
Issue
When inserting a new record into a table, through a page created with MX Kollection 3, I get an error message saying: "Internal error.". The developer details state:"tNG_fields.evaluateFieldExpr: Invalid expression".

Reason
This happens because a numeric field has been added to the transaction, and the expression that it uses as a value is incorrect.
Solution
In order to resolve this issue, you must edit the Add transaction fields server behavior which contains the expression for the field. In the dialog box that opens, either set the column type to text, and the expression will be taken into account as a string, or leave the type as numeric, and change the expression. Expressions used in the Add transaction fields for numeric types can only contain numeric characters (0-9) and the characters +, -, *, /, (, ) and . (dot). You can also use mark-ups that are evaluated to numeric.