Rovicorp signature

I am trying to get data from rovicorp (www.rovicorp.com) for Movie/Music info. For this I have to calculate a signature that is an MD5 hash made out of apikey, secret key and unix timestamp. I have tried the following code but get an authorization denied. apkikey and secretkey are changed to xxx because these are personal. If you are interested your self you can get an account free and use it. For testing I have put the result in a message box. If I try it using an url with a calculated hexsig on the rovi itself it works. I think the problem is the unix timestamp or the MD5 hash. Anybody got a suggestion what the problem could be?

function unixtime(extends d as date) double
Return (d.TotalSeconds - 2082844800 - (d.GMTOffset * 3600))
end function

dim apikey As String = “xxxxxxxxx”
dim secretkey As String = “xxxxxxxxxx”
dim unixtime As new Date

dim unixtimestamp as String
unixtimestamp = Format(unixtime.unixtime,"#")

//MsgBox unixtimestamp

dim sig As String = MD5(apikey + secretkey + unixtimestamp)
dim hexsig As String = EncodeHex(sig)

dim mysocket As new HTTPSocket
dim mywebpage As String = “http://api.rovicorp.com/search/v2.1/video/search?entitytype=movie&query=the+matrix&rep=1&size=20&offset=0&language=en&country=US&format=json&apikey=” + apikey + “&sig=” + hexsig
//MsgBox (mywebpage)
dim result As String
result = mysocket.Get(mywebpage,30)
MsgBox(result)