Did you set the TRIS register at least for those CS and Cslave pin.??? Did you disable them at the begining of your program before access to them.

There's some slight difference between every 93C familly when you want access to them...

93c06 93C46
Code:
        'read from eeprom
        CS = 1                          
        Shiftout DI, CLK, MSBFIRST, [%110\3, addr\6]       
        Shiftin DO, CLK, MSBPOST, [B0,B1]                                    
        cs=0
93c56
Code:
     'Read from EEPROM                                
     CS = 1 
     Shiftout DI, CLK, MSBFIRST, [%110\3, addr\8]
     Shiftin DO, CLK, MSBPOST, [b0,b1]                                       
     CS = 0