I did read and used your function(Thank you btw, it was your code that fixed the lockups), I just adapted it abit to make it easier for me... eitherway it works the same way. and I did set user_level aswell as user_name:

unsigned char xdata user_name[16*userlimit] _at_ 0x00E1;				//stores user name.16*userlimit.
unsigned char xdata user_level[userlimit] _at_ 0x03B1;				//store user level.1*userlimit.

 

I just tried a copy paste of both the codes you wrote

void wreeprom(unsigned short ads, unsigned char c)
{
	EECON |= (1<<1);		/* EEE */
	*((unsigned char xdata *)ads) = c;
	EECON = 0x54;			/* SPECIAL SEQUENCE */
	EECON = 0xA4;
	while (EECON & (1<<0)); 	/* EEBUSY */
	EECON = 0x00;			/* brute force */
}

 

and

void wreeprom(unsigned short ads, unsigned char c)
{
#ifdef _i8051
#if   defined(_AT89C5131_)
	EECON |= (1<<1);		/* EEE */
	*((unsigned char xdata *)ads) = c;
	EECON = 0x54;			/* SPECIAL SEQUENCE */
	EECON = 0xA4;
	while (EECON & (1<<0));	/* EEBUSY */
//	EECON &= ~(1<<1);		/* EEE */
	EECON = 0x00;			/* brute force */
#elif defined(_AT89S8252_)
	WMCON |= (1<<3);		/* EEMEN */
	WMCON |= (1<<4);		/* EEMWE */
	*((unsigned char xdata *)ads) = c;
	while ((WMCON & (1<<1)) == 0) ;	/* WDTRST */
	WMCON &= ~((1<<3)|(1<<4));	/* EEMEN | EEMWE */
#else
#error _i8051 without EEPROM
#endif
#endif
}

 

both are Just with these few alterations:

A)EECON is not bit addressable for instead of EEE I wrote EECON=0x02;
B)removed the #define AT89S8252 part as it is irrelevant to my MCU
C)added the AUXR to read sessions as request by the datasheet:

http://www.keil.com/dd/docs/datashts/atmel/at89c5131_ds.pdf

in pages 40 and 48.

they all give the same result as the function I used (thats based on what you said so no surprise there)