This error occurs when location keywords before, after, at beginning, at end are used along with modifier Replace or Delete.
Do not use location keywords with modifiers Replace and Delete.
Example
[#Menu: Gateway Of Tally]
Add: Item: "MyReport": Display: MyReport
[Report: MyReport]
Use : Balance Sheet
Replace: Form: Before
In the above example, the modifier Replace does not take location keywords. Hence the message error T0037: Location keyword 'Before' is not supported for the modifier 'Forms'.
The code is corrected by removing the location keyword with an appropriate form.
[#Menu: Gateway Of Tally]
Add: Item: "MyReport": Display: MyReport
[Report: MyReport]
Use : Balance Sheet
Replace: Form: Balance Sheet: TrialBalance
