I have a form checker script working on all my drop downs and all working fine, as they all need to have been used, but when it comes to the radio buttons, they dont work for some reason, the form checker doesnt see the value 0 as below and allows the form to submit.

Code:
else if (document.form2.potentialoutcome.value == "0")
{
	alert("Potential level of injury - Please complete all required fields");
	window.location="detail.php?ID=<?=$report_ID ?>#potentialoutcome";
    return false;
}
else if (document.form2.likelihood.value == "0")
{
	alert("Likelihood of injury - Please complete all required fields");
	window.location="detail.php?ID=<?=$report_ID ?>#likelihood";
    return false;
}

<div style="position:relative; width:950px; height:200px; margin-top:30px;">
<a name="potentialoutcome" id="potentialoutcome"></a>
<div style="position:relative; float:left; width:210px; height:200px; line-height:30px;">
<span style="color:#900">*</span> Potential level of injury?</div>
<div style="position:relative; float:right; width:735px; height:170px; line-height:30px; padding-top:0px;">
<input name="potentialoutcome" type="radio" value="0" checked="checked"> Select Option<br/>
<input name="potentialoutcome" type="radio" value="Minor"> Minor<br/>
<input name="potentialoutcome" type="radio" value="First aid"> First aid<br/>
<input name="potentialoutcome" type="radio" value="Lost time (incl >3 days)"> Lost time (incl >3 days)<br/>
<input name="potentialoutcome" type="radio" value="Major injury"> Major injury<br/>
<input name="potentialoutcome" type="radio" value="Fatality"> Fatality</div>
</div>

<div style="position:relative; width:950px; height:200px; top:10px;">
<a name="likelihood" id="likelihood"></a>
<div style="position:relative; float:left; width:210px; height:200px; line-height:30px;">
<span style="color:#900">*</span> Likelihood of injury?</div>
<div style="position:relative; float:right; width:735px; height:170px; line-height:30px; padding-top:0px;">
<input type="radio" name="likelihood" value="0" checked> Select Option<br/>
<input type="radio" name="likelihood" value="Very unlikely"> Very unlikely<br/>
<input type="radio" name="likelihood" value="Unlikely"> Unlikely<br/>
<input type="radio" name="likelihood" value="Possible"> Possible<br/>
<input type="radio" name="likelihood" value="Likely"> Likely<br/>
<input type="radio" name="likelihood" value="Very Likely"> Very Likely</div>
</div>
http://www.whhazardreport.co.uk/mana...p?ID=66#hazard