Custom Stored Procedure error "Connection is busy with results for another command"

I have two servers that I am executing the same custom stored procedure on a mssql database. I am using [Microsoft][ODBC Driver 11 for SQL Server] as my driver on both servers. Both servers have the same code repository. the only difference is one executes the stored procedure correctly, the other doesn’t.

Here is the code from my controller:

$command = Yii::app()->db->createCommand('

EXEC	[dbo].[GloveDealerBulkReassignment]

@DealerID = '.$_POST['Dealers']['did'].',

@UserID = '.Yii::app()->user->getId().',

@InventoryList = \''.$xmlEl.'\'          // <-- this is a xml string


$sessionInfo = $command->execute();

if($sessionInfo != 0){

	$modelAndMessage["message"] = "SP not completed. sessionInfo = ".$sessionInfo;



	$modelAndMessage["message"] = "SP completed.";


This is the error I get from one of my servers:

Any idea why only one server would cause this error? Or is there something else I should be looking at?