Paypal sandbox producing message 3005 - paypal

Question

I have been struggling with this issue for quite a while now. I am trying to test a PayPal button implementation with their Sandbox, and have the following code:
<form action="https://www.sandbox.paypal.com/cgi-bin/webscr" method="post" target="_top">
<input type="hidden" name="cmd" value="_xclick-subscriptions">
<input type="hidden" name="business" value="email#example.com">
<input type="hidden" name="lc" value="GB">
<input type="hidden" name="item_name" value="Item Name">
<input type="hidden" name="no_note" value="1">
<input type="hidden" value="http://XX.XX.XX.XX" name="return">
<input type="hidden" name="src" value="1">
<input type="hidden" name="currency_code" value="GBP">
<input type="hidden" name="bn" value="PP-SubscriptionsBF:btn_subscribe_LG.gif:NonHostedGuest">
<table>
<tr><td><input type="hidden" name="on1" value="First">First Name</td></tr><tr><td><input type="text" name="os1" maxlength="200"></td></tr>
<tr><td><input type="hidden" name="on2" value="Last">Last Name</td></tr><tr><td><input type="password" name="os2" maxlength="200"></td></tr>
<tr><td><input type="hidden" name="on0" value="Frequency">Frequency</td></tr><tr><td><select name="os0">
<option value="Weekly">Weekly : £10.00 GBP - weekly</option>
<option value="Monthly">Monthly : £25.00 GBP - monthly</option>
<option value="Yearly">Yearly : £250.00 GBP - yearly</option>
</select> </td></tr>
</table>
<input type="hidden" name="currency_code" value="GBP">
<input type="hidden" name="option_select0" value="Weekly">
<input type="hidden" name="option_amount0" value="10.00">
<input type="hidden" name="option_period0" value="W">
<input type="hidden" name="option_frequency0" value="1">
<input type="hidden" name="option_select1" value="Monthly">
<input type="hidden" name="option_amount1" value="25.00">
<input type="hidden" name="option_period1" value="M">
<input type="hidden" name="option_frequency1" value="1">
<input type="hidden" name="option_select2" value="Yearly">
<input type="hidden" name="option_amount2" value="250.00">
<input type="hidden" name="option_period2" value="Y">
<input type="hidden" name="option_frequency2" value="1">
<input type="hidden" name="option_index" value="0">
<span id='signupButton'></span>
</form>
This successfully redirects me to the PayPal checkout, but once logged in with my Sandbox buyer account, it produces the following problem consistently:
I've done everything suggested in the error page, but still no luck. Am I missing something?

Answer 1

This is a generic (and ancient) PayPal "our process died attempting to produce a web page" error. Presumably you have some incorrect input or unusual circumstance that causes the crash, but you would be doing everyone a favor if you report this bug to PayPal so that they can fix it (to give a useful error back rather than crashing).
That said, to diagnose I would recommend stripping down to a super-simple button and if that works, try re-introducing the complexity of your button to see what triggers the crash.
However, since the crash happens after login it may also be a bad buyer account (or even a bad seller/buyer account combination) or some such that triggers the edge condition. So I would also try with a different buyer account.