My guess would be that the error you got was "XML parsing: line 9, character 13, unexpected end of input"? This is because your xml is malformed.

Your xml should look like this:
<?xml version="1.0" encoding="utf-8"?>
<XMLScript Version="2.0" />
<Command Name="xxxxxxxxxxxxxxxxxxxxxxxxxx" />
<Print WaitForJobToComplete="false" Timeout="2000" />
<Format>D:\xxx\xxxxxx\xxxx\xxxxx</Format>
<PrintSetup>
<NumberSerializedLabels>108</NumberSerializedLabels>
<Printer>XXX_XXX_XX</Printer>
</PrintSetup>
Note the extra /'s at the end of Command and Print.

You'll need tpo fix your XML first before you can query it using XQuery. Then you can actually store the xml as an xml datatype and query it directly.

For example:
CREATE TABLE #XML (XMLField xml);
GO

INSERT INTO #XML
VALUES('<?xml version="1.0" encoding="utf-8"?>
<XMLScript Version="2.0" />
<Command Name="xxxxxxxxxxxxxxxxxxxxxxxxxx" />
<Print WaitForJobToComplete="false" Timeout="2000" />
<Format>D:\xxx\xxxxxx\xxxx\xxxxx</Format>
<PrintSetup>
<NumberSerializedLabels>108</NumberSerializedLabels>
<Printer>XXX_XXX_XX</Printer>
</PrintSetup>');
GO

SELECT P.N.value('.','int') AS NumberSerializedLabels
FROM #XML X
  CROSS APPLY X.XMLField.nodes('PrintSetup/NumberSerializedLabels') P(N);
GO

DROP TABLE #XML;
GO