Getting a yellow triangle. ajax timeout?

Hi I am getting a yellow triangle when I do a GL inquiry. I have quite a number records
in the database but I can only get about 15 days worth i.e (01/01/11 - 01/15/11) any greater
and I get a yellow triangle with an exclamation mark.

Doing a search on the forum I have tried disabling java script.
This seems to solve the problem I can get over two months of record, without any errors displayed.
(with decent loading speed)
I have turn on the debug go_debug in the config.php but there is no error either.

I have tried increasing the tout value to 600000 in the util.js file but there do not seem to be any
difference.

I have also tried to increasing the memory values in phpmyadmin my.ini file
key_buffer              = 256M
max_allowed_packet      = 10M
table_cache             = 512
sort_buffer_size        = 32M
net_buffer_length       = 1M
read_buffer_size        = 1M
read_rnd_buffer_size    = 1M
myisam_sort_buffer_size = 32M
innodb_buffer_pool_size         = 256M
innodb_additional_mem_pool_size = 20M

and the php.ini
post_max_size = 128M

Does anyone have a solution or suggestion that I can try?

It would be greatly appreciated