Division by zero?

Har gjort en liten räknare här:
http://www.hisdivineshadow.com/misc/causality.asp

Och, när jag matar in siffrorna 10000 och -0,0001 får jag ett "division by zero" error, eller det fick jag på en annan server, på denna server säger det bara "internal error 500"

Här är koden:

[B]formuläret:[/B]
<form action="causality.asp?Calculate=yes" method="post">
			<table border="0" cellpadding="1" cellspacing="0">
				<tr>
					<td>
						<font face="Verdana" size="1">Speed of signal:</font>
					</td>
				</tr>
				<tr>
					<td>
						<%IF request("Calculate") = "yes" THEN%>
						<input type="text" name="v" value="<%=Request("v")%>">
						<%ELSE%>
						<input type="text" name="v" value="1">
						<%END IF%>
					</td>
				</tr>
				<tr>
					<td>
						<font face="Verdana" size="1">relative velocity between transmitter and 
							reciever(negative numbers if they are moving towards each other): </font>
					</td>
				</tr>
				<tr>
					<td>
						<%IF request("Calculate") = "yes" THEN%>
						<input type="text" name="vo" value="<%=vo%>"><font face="Verdana" size="1">
							<%ELSE%>
							<input type="text" name="vo" value="">
							<%END IF%>
					</td>
				</tr>
				<tr>
					<td>
						<font face="Verdana" size="1">Result:</font>
					</td>
				</tr>
				<tr>
					<td>
						<%IF request("Calculate") = "yes" THEN%>
						<input type="text" name="answer" value="<%=Result%>" ID="Text1">
						<%ELSE%>
						<input type="text" name="answer" value="" ID="Text2">
						<%END IF%>
					</td>
				</tr>
				<tr>
					<td>
						<input type="submit" value="Calculate">
					</td>
				</tr>
			</table>
		</form>

[B]Koden som räknar:[/B]
v = cdbl(replace(request("v"),".",","))
vo = cdbl(replace(request("vo"),".",","))

Result = ((v + vo)/(1 + (vo * v)))