Strange behaviour in TIMER0 ISR

Hi all, I have a problem with the ISR of TIMER0.
I'm using keil uVision2 and my target is SIlicon Laboratories C8051F040.

I've tried to make a very simple project in assembler to use Timer0 ISR (below you will find the relatives code) and it works fine.

If I try to translate this project in C, the ISR is called just a few time (around 10 or 11 times) but after this, it is never called!

But... if, instead of Timer0, I use Timer1, all work fine both in C and in Assembler

I can't understand why?
There is someone wich can help me?

NOTE: Is not important the reload value so i don't set it, and although if I set this value the behaviour not change.
NOTE: Timer0 is a 16-bit timer
NOTE: In the examples below I've hided the not relevant code like oscillator init, port init,...

--------------
ASSEMBLY CODE:
--------------

        ...
        ...
        ...

;TIMER_0 Overflow
ORG 0x000B
        LCALL TIMER0_INT

        ...
        ...
        ...


TIMER_INIT:
        NOP

;------
;TIMER0
;TIMER1
;------
        MOV SFRPAGE, #TIMER01_PAGE
        MOV TCON, #01000101b
        MOV TMOD, #00100001b

        ...
        ...
        ...

INTERRUPTS_INIT:
        MOV IE, #10010111b
        MOV IP, #00000000b
        MOV EIE1, #00001000b
        MOV EIE2, #01000000b
        MOV EIP1, #00001000b
        MOV EIP2, #00000000b

        ...
        ...
        ...


MAIN:
        MOV SFRPAGE, TIMER01_PAGE
        SETB TR0                        ;START TIMER

        JMP $


        ...
        ...
        ...


TIMER0_INT:

        RETI

-------
C CODE:
-------

...
...
...




void Timer_Init()
{
    SFRPAGE   = TIMER01_PAGE;
    TCON      = 0x45;
    TMOD      = 0x21;
    CKCON     = 0x18;
    SFRPAGE   = TMR2_PAGE;
    TMR2CN    = 0x04;
    TMR2CF    = 0x08;
    SFRPAGE   = TMR3_PAGE;
    TMR3CN    = 0x04;
    TMR3CF    = 0x08;
    SFRPAGE   = TMR4_PAGE;
    TMR4CN    = 0x04;
    TMR4CF    = 0x08;
}




...
...
...




void Interrupts_Init()
{
    IE        = 0x97;
    EIE1      = 0x08;
    EIE2      = 0x40;
    EIP1      = 0x08;
}




...
...
...





void main(void){




        Timer_Init();
        Interrupts_Init()
        ...
        ...
        ...




        SFRPAGE = TIMER01_PAGE;
        TR0 = 1;                        //START TIMER




        while(1);




}






void timer0_int(void) reentrant interrupt 1 {




}