Not able to move on Next Page

Hello Jason,

I am trying to jump on next page but after taking all the variable for moving to next page it shows "Warning! Received a status code of: 500 "

Here is the URL http://centuryfurniture.com/products.aspx?Search=TRUE&CollNo=AC&CollectionName=Thomas+O%27Brien&section=WOOD

Please suggest me how to move on next page.

and I am taking all the variables like
__EVENTTARGET
__EVENTARGUMENT
__LASTFOCUS
__VIEWSTATE
__EVENTVALIDATION
pageHeader$inspNavGall_current
pageHeader$screensize
pageHeader$currTab
pageHeader$currBTN
pageHeader$prevTab
hPageIndex

Thanks
Shyam