<p>I'm getting a <strong><code>Connection Busy With Results From Another Command</code></strong> error from a SQLServer Native Client driver when a SSIS package is running. Only when talking to SQLServer 2000. A different part that talks to SQLServer 2005 seems to always run fine. Any thoughts?</p>

Microsoft KB article 822668
is relevant here:
FIX: "Connection is busy with results for another command" error message occurs when you run a linked server query
Symptoms
Under stress conditions, you may receive the following error message when you perform linked server activity:
```
```
Server: Msg 7399, Level 16, State 1, Procedure <storedProcedureName>, Line 18 OLE DB provider 'SQLOLEDB' reported an error. 
OLE/DB Provider 'SQLOLEDB' ::GetSchemaLock returned 0x80004005:

OLE DB provider SQLOLEDB supported the Schema Lock interface, but returned 0x80004005 for GetSchemaLock .]. 
OLE/DB provider returned message: Connection is busy with results for another command 
OLE DB error trace [OLE/DB Provider 'SQLOLEDB' ::CreateSession returned 0x80004005.
```
```
Note
The OLE DB source of the error may vary. However, all variations of the error message include the text "Connection is busy with results for another command".
Resolution
To resolve this problem, obtain the latest service pack for Microsoft SQL Server 2000.
As noted there, the problem was first corrected in SQL Server 2000 Service Pack 4.
This blog post
by Mark Meyerovich, a Senior Software Engineer at RDA Corp, also provides some insight (now archived, because the original link went dead):
SQL Server service pack upgrade
A quick search on Google turns up the following article (
http://support.microsoft.com/kb/822668
):
  FIX: "Connection is busy with results for another command" error message occurs when you run a linked server query.
It basically implies the issue is a bug and recommends an upgrade to Service Pack 4. We have started out with SQL Server 2000 SP3 and we do have some linked servers in the equation, so we give it a try. After the upgrade to SP4 – same result.