Hi,
I expect the Rx line to be input. Thus it can´t be stuck by the PIC. Well, errors will hapen, but I don´t expect this.
Are you sure it´s the PIC that causes the problem on the Rx line?
* Did you read all the microchip errata documents?
* did you follow all the design rules given in the datasheet
* Can there be a Rx/Tx mix or a polarity problem?
* Did you try to install ESD protection?
What did you try at all?
You don´t give much information that we can validate.
Hint:
Instead of shouting that this is "urgent" (which may sound like you want to make other people - who help for free - responsible for delays).
... you should show schematic, photos, PCB layout, scope pictures, detailed debugging results, ethernet logs ...
it will motivate members to browse through the informations and you will get faster response.
Klaus