Can anyone help me to understand what this error means? It happens when i
try to insert a row in a specific worksheet.

-To prevent possible loss of data, Microsoft Office Excel cannot shift
nonblank cells off the worksheet. Try to locate the last nonblank cell by
pressing CTRL+END, and delete or clear all cells between the last cell and
the end of your data. Then select cell A1 and save your workbook to reset
the last cell used. Or, you can move the data to a new location and try
again.

This error does not make sense to me because the entire worksheet is not
'full'.