JPGraph error.

Hey guys.

In my system we´ve got an option of getting charts of some data and it´s 
many options.

My problem is that it works fine on my test server but in my client´s server 
it gives me the following error as you can see.

*** glibc detected *** /var/www/html/bin/httpd: munmap_chunk(): invalid 
pointer: 0x0a319b78 ***
======= Backtrace: =========
/lib/libc.so.6(cfree+0x1bb)[0x17d81b]
/var/www/html/modules/libphp5.so(_efree+0x7e)[0x4bd35e]
/var/www/html/modules/libphp5.so(zend_hash_destroy+0x5c)[0x4dbd7c]
/var/www/html/modules/libphp5.so(_zval_dtor_func+0x55)[0x4d27e5]
/var/www/html/modules/libphp5.so(_zval_ptr_dtor+0x4f)[0x4c7f0f]
/var/www/html/modules/libphp5.so(zend_hash_destroy+0x36)[0x4dbd56]
/var/www/html/modules/libphp5.so(destroy_zend_class+0x3a)[0x4cb86a]
/var/www/html/modules/libphp5.so[0x4dba07]
/var/www/html/modules/libphp5.so(zend_hash_reverse_apply+0x57)[0x4dbb47]
/var/www/html/modules/libphp5.so(shutdown_executor+0x404)[0x4c85c4]
/var/www/html/modules/libphp5.so(zend_deactivate+0x93)[0x4d2e83]
/var/www/html/modules/libphp5.so(php_request_shutdown+0x1e0)[0x497bd0]
/var/www/html/modules/libphp5.so[0x548927]
/var/www/html/bin/httpd(ap_run_handler+0x59)[0x8074bf9]
/var/www/html/bin/httpd(ap_invoke_handler+0x67)[0x8077d67]
/var/www/html/bin/httpd(ap_process_request+0x178)[0x808e308]
/var/www/html/bin/httpd[0x808b60b]
/var/www/html/bin/httpd(ap_run_process_connection+0x59)[0x807bb19]
/var/www/html/bin/httpd[0x80a1240]
/var/www/html/bin/httpd[0x80a1537]
/var/www/html/bin/httpd(ap_mpm_run+0x880)[0x80a1e90]
/var/www/html/bin/httpd(main+0x845)[0x80629d5]
/lib/libc.so.6(__libc_start_main+0xdc)[0x129f2c]
/var/www/html/bin/httpd(apr_os_proc_mutex_put+0x5d)[0x8061be1]
======= Memory map: ========
[Thu Feb 25 16:17:20 2010] [notice] child pid 2850 exit signal Aborted (6)

Does anybody know why is it happening?

Thanks in advance.
João.