Q:

Collection fails when using a more restricted admin user

I have the following collection which helps implement a custom report.  
<?php

class VMR_Customreports_Model_Resource_Productsordered_Collection
    extends Mage_Reports_Model_Resource_Order_Collection
{
    public function __construct()
    {
        parent::__construct();
        $this->_init('sales/order_item');
    }

    public function setDateRange($from, $to)
    {
        $this->_reset();
        $this->getSelect()
            ->joinInner(
                array('i' => $this->getTable('sales/order_item')),
                'i.`order_id` = main_table.`entity_id`'
            )
            ->where("main_table.created_at BETWEEN '" . $from . "' AND '" . $to . "'")
            ->where('main_table.status != \'canceled\'')
            ->where('main_table.customer_email NOT LIKE \'%@v2cigs.%\'')
            ->where('i.parent_item_id IS NULL')
            ->columns(array(
                'myname' => 'i.name',
                'ordered_qty' => 'sum(i.qty_ordered)',
                'ordered_money' => 'sum(i.`price`*i.qty_ordered)'))
            ->group('i.name');

        return $this;
    }

    public function setStoreIds($storeIds)
    {
        if ($storeIds)
            $this->addAttributeToFilter('i.store_id', array('in' => (array)$storeIds));

        return $this;
    }

}

When I login as full admin, it selects the right data but when I login as a more restricted user I get an error about, "Integrity constraint violation: 1052 Column 'store_id' in where clause is ambiguous".
I can understand that it's talking about store_id being present both in the order_item table and in the order table, but I am specifying the table to pull from when using store_id.  
Furthermore, the error happens right at the join.  If I comment out the store_id code I still get the error.  Why?

A:

If you are using the Enterprise Edition, the AdminGws module is applying store scope filters so admins are only able to access data they are authorized to see.
Also, you probably want to remove your __construct() method. See below for some additional information.  
Background:
You are extending from Mage_Reports_Model_Resource_Order_Collection.
This class uses the sales/order table (that is, sales_flat_order as the main table.   
 $this->getSelect()->from(array('main_table' => $this->getMainTable()));

The main table is actually fetched from the associated resource model:
public function getMainTable()
{
    if ($this->_mainTable === null) {
        $this->setMainTable($this->getResource()->getMainTable());
    }

    return $this->_mainTable;
}

So the resource model is responsible to supply the main table name.
Mage::getResourceModel($this->getResourceModelName()) is used to collect the resource model.
So what does getResourceModelName() return?
It returns the value that was set by the _init() call.  
protected function _init($model, $resourceModel = null)
{
    $this->setModel($model);
    if (is_null($resourceModel)) {
        $resourceModel = $model;
    }
    $this->setResourceModel($resourceModel);
    return $this;
}

In your class, you are overriding the _init() call of the parent class:
$this->_init('sales/order_item');

In effect, you are specifying that your collection should use the order item resource model, which will return the table sales/order_item as the main table.
Because of your _init() call you are joining the sales_flat_order_item table with itself.
Fixing that by removing the _init() call, or in fact the whole __construct() override, will probably fix that issue for you.

