This error occurs when a definition is described with no definition type.
Add the required description type in the code. Use Tally.Developer 9 to write the code as it has the intelligence to show syntax errors.
Example
[ : MyField]
Set as: "Tally Solutions"
Since there is no description type given in this code the message error T0004: The description type is empty. appears.
To correct the code a description type is added as given below:
[Field: MyField]
Set as: "Tally Solutions"