I have just found out that the problem is caused by the declaration of frame buffer (1500 Bytes) that is before the decraration of the structures. If I take what before didn't work and move the frame buffer after the decraration of the structures, it works correctly.

This declaration causes the error:

#define ETH_FRM_SIZE 1500

void main(void) {
   
   BYTE EthFrmBuf[ETH_FRM_SIZE];
   BYTE broadcast_IP[4] = {255,255,255,255};
   BYTE zero_ip[4] = {0, 0, 0, 0};
   BYTE ip_addrr[4];
   ...
}
 

This declaration doesn't cause the error:

#define ETH_FRM_SIZE 1500

void main(void) {
   
   BYTE broadcast_IP[4] = {255,255,255,255};
   BYTE zero_ip[4] = {0, 0, 0, 0};
   BYTE ip_addrr[4];
   BYTE EthFrmBuf[ETH_FRM_SIZE];
   ...
}