An over connection violation is letting you know that the connections described in your schematic don't match your PCB layout. Specifically that your PCB has too many connections.
Here is a simple schematic:
And the corresponding layout for it:
The schematic has R1-pin2 connected to R2-pin1 and R3-pin2 connected to R4-pin1. The layout has all four of these pins connected together. The connection to all four pins is the over connection.
To fix the error you need to remove the trace connecting the R1-pin2, R2-pin1 trace to R3-pin2, R4-pin1.