Xlib Connection refused - Urgent

[Naheed Vora <nv@xxxxxxxxxxxxxx>]

void main() {

const char *ps_argv[] = { "pgaccess", "imart_db", 0 };

const char *ps_envp[] = { "PATH=/bin:/usr/bin","USERNAME=imart",
"DISPLAY=:0", 0 };
execve("/usr/bin/pgaccess", ps_argv, ps_envp);

}	

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Error Encountered
-------------

Xlib: connection to ":0.0" refused by server
Xlib: Client is not authorized to connect to Server
Application initialization failed: couldn't connect to display ":0"
Error in startup script: invalid command name "image"
    while executing
"image create bitmap dnarw -data  {
#define down_arrow_width 15
#define down_arrow_height 15
static char down_arrow_bits[] = {
	0x00,0x80,0x00,0x80,0x0..."
    (file "/usr/lib/pgsql/pgaccess/main.tcl" line 5)

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Can anybody help me out of this... Is there any procedure to authorize
my program with X...

TIA,
nv