Getting to page 2

Somehow i am not able to go to the second page of the following url: http://www.zo$$over.nl/servie/servie/belgrado (replace $$ with nothing, click 'volgende' at the bottom of the page).

On clicking 'volgende' a javascript function is executed that connects to http://www.zo$$over.nl/Services/Endeca/EndecaQueryService.asmx/Query (replace $$ with nothing) with the following post value:

{"request":{"__type":"NetMatch.Zoover.Endeca.Web.EndecaQueryServiceRequest","QueryString":"Ns=pTestimonialCountLan1|1&N=0+82+3+10501037+10404181+10260853&dims=530&props=16316&No=40","PlaceHolderIdList":["refinements-placeholder","descriptors-placeholder","endeca-list","entity-sort","entity-paging-top-no-entity","entity-paging-bottom","radius-selection-placeholder"]},"pageContext":{"__type":"NetMatch.Zoover.Web.Atlas.AtlasPageContext","EntityLevelString":"destination","EntityId":60853,"PageCode":"destination","PageSubcode":"accommodations","Path":"","CurrentSiteVariation":"nl","SupplierLinksAvailable":"False","PageSemanticName":"destination-accommodations","EntityType":""},"entityHasAdlinks":true}

for some reason this does not work i keep getting an 500 with the message '
Index was outside the bounds of the array.'

I tried several options, including putting the post data in a key field instead of value. Running the ss scraper proxy and creating the scrapeable files from the proxy, and i tried to use a program called fiddler which shows connections information for each http request. None of the things i tried have had any success. So at this point i am stuck.

Any help would be greatly appreciated.

Kind regards
Nebu