Problem solved. The problem was the syntax error in reg752.inc file. There are differences in syntax between the assemblers when they define SFR register (the I2STA). In this case MetaLink used:

         RSTP     BIT    0F8H   
         RSTR     BIT    0F9H   
         MAKSTP   BIT    0FAH   
         MAKSTR   BIT    0FBH   
         XACTV    BIT    0FCH   
         XDATA    BIT    0FDH   
         RIDLE    BIT    0FEH

Whereas Keil Assembler handles a little different:

         _XSTP    BIT    0F8H   
         _XSTR    BIT    0F9H   
         MAKSTP   BIT    0FAH   
         MAKSTR   BIT    0FBH   
         XACTV    BIT    0FCH   
         _XDATA   BIT    0FDH   
         _IDLE    BIT    0FEH

Thanks you for all inputs. Have a great one.