18F4550 - Does strange things on D ports

[NL2TTL]

I have the following code written.

When the debug code is send, the D6 & D7 port will also become HIGH.
Why is this happening?

code:

'****************************************************************
'*  Name    : UNTITLED.BAS                                      *
'*  Author  : [select VIEW...EDITOR OPTIONS]                    *
'*  Notice  : Copyright (c) 2009 [select VIEW...EDITOR OPTIONS] *
'*          : All Rights Reserved                               *
'*  Date    : 20-10-2009                                        *
'*  Version : 1.0                                               *
'*  Notes   :                                                   *
'*          :                                                   *
'****************************************************************
Include     "modedefs.bas"

Define  OSC             20

DEFINE  DEBUG_REG       PORTB
DEFINE  DEBUG_BIT       6
DEFINE  DEBUG_BAUD      9600
DEFINE  DEBUG_MODE      1


DEFINE  LCD_DREG        PORTB
DEFINE  LCD_RSREG       PORTC
DEFINE  LCD_RSBIT       6
DEFINE  LCD_EREG        PORTC
DEFINE  LCD_EBIT        7
DEFINE  LCD_BITS        4
DEFINE  LCD_LINES       2
DEFINE  LCD_COMMANDUS   2000


RS232_In VAR         PORTB.5

StatusLED   VAR         PORTB.7


DigiData            VAR     BYTE[74]

x var byte
i VAR Byte


adcon1 = $0F


Init:

    debug "Startup Alarm systeem V1.01",13,10
    
    Lcdout $FE, $01, "Rekavo"
    Lcdout $FE, $C0, "Bericht systeem" 
    
    PAUSE 500
    
    FOR x = 0 to 4
        High Statusled
        PAUSE 500
        LOW Statusled
        PAUSE 500
    NEXT x
         
Goto Main

Main:

    SERIN RS232_In,N9600,10,Main,DigiData[0]
    
    for i = 1 to 74
     SERIN RS232_In,N9600,1,Main,DigiData[i]
    next i
    
    For i = 0 to 74
        DEBUG DigiData[i]
    NEXT i

    DEBUG 13,10
  
    IF (DigiData[0] = $02) AND (DigiData[74] = $03) Then
        Debug "Juiste string ontvangen",13,10  
  
        Lcdout $FE, $01, DigiData[4],DigiData[5],DigiData[6],DigiData[7],DigiData[8],DigiData[9],DigiData[10],DigiData[11],DigiData[12],DigiData[13],DigiData[14],DigiData[15],DigiData[16],DigiData[17],DigiData[18],DigiData[19]
        Lcdout $FE, $C0, "Tijd: ", DigiData[70],DigiData[71],":",DigiData[72],DigiData[73]  
        
        PAUSE 2000
        
        Lcdout $FE, $01, " "
        Lcdout $FE, $C0, " "
                                        
    ELSE
    
        Debug "Onjuiste string ontvangen",13,10
   
    endif

Goto Main

end

See the attachment for the configuration bits: