Question: I'm still new to map Usage.. How could this code be bulkified?

```
trigger OppyStatusCheck on Opportunity (before insert, before update) {
    for(Opportunity opp : Trigger.new) {
        if(opp.StageName=='Closed Won') {
            List<Quote> quoteChilds = [SELECT Id, Name from Quote where OpportunityId=:opp.Id and Status='Accepted'];
            if(QuoteChilds.size() < 1) {

                String errorMessage = 'At least one accepted quote required for closing an opportunity!';
                opp.addError(errorMessage);
            }
        }           
    }
}

```

Answer: 
Issues:

1. URL No Longer Exists
	* Error is happening because your path to the page is incorrect and is missing the leading `/` which creates a URL which is relative to the current page rather than relative to the host.
2. Path to the page outside of the managed package namespace
	* The default VF namespace is `c__` and you can specify this in your page path. This allows you to avoid hardcoding a fully qualified URI.

`<apex:commandButton value="Open" onclick="window.open('/apex/c__MyPage'); return false;" />`

Related: [How to redirect to default namespace vf page from managed package vf page?](https://salesforce.stackexchange.com/questions/22132/)
I'm not sure that this will solve your problem but try this one :

```
< apex:commandButton value="Open" onclick="window.open('{!$Page.MyPage}'); return false;" />

```