umbraco 4.0.3 IIS6 W2K3R2 .net 3.5 sp1

Hi, on an xslt template I'm trying to supply umbraco.library:RenderTemplate with /macro/bannerNodeId (as per method signature). The macro parameter is defined as a number. Not sure what's wrong with this (see exception below when trying to save xslt). I also tried to passing an xml node as parameter, then assign /macro/xmlNode/@id to bannerNodeId, no luck either. Any help really appreciated :-)

<xsl:template match="/">

<xsl:variable name="bannerNodeId" select="/macro/bannerNodeId"/>

<xsl:value-of select="umbraco.library:RenderTemplate($bannerNodeId)" disable-output-escaping="yes"/>
</xsl:template>

exception stack:

System.OverflowException: Value was either too large or too small for an Int32.
at System.Convert.ToInt32(Double value)
at System.Double.System.IConvertible.ToInt32(IFormatProvider provider)
at System.Convert.ChangeType(Object value, Type conversionType, IFormatProvider provider)
at System.Xml.Xsl.Runtime.XmlQueryRuntime.ChangeTypeXsltArgument(XmlQueryType xmlType, Object value, Type destinationType)
at System.Xml.Xsl.Runtime.XmlQueryContext.InvokeXsltLateBoundFunction(String name, String namespaceUri, IList`1[] args)
at (XmlQueryRuntime {urn:schemas-microsoft-com:xslt-debug}runtime, XPathNavigator {urn:schemas-microsoft-com:xslt-debug}current)
at Root(XmlQueryRuntime {urn:schemas-microsoft-com:xslt-debug}runtime)
at Execute(XmlQueryRuntime {urn:schemas-microsoft-com:xslt-debug}runtime)
at System.Xml.Xsl.XmlILCommand.Execute(Object defaultDocument, XmlResolver dataSources, XsltArgumentList argumentList, XmlSequenceWriter results)
at System.Xml.Xsl.XmlILCommand.Execute(Object defaultDocument, XmlResolver dataSources, XsltArgumentList argumentList, XmlWriter writer, Boolean closeWriter)
at System.Xml.Xsl.XmlILCommand.Execute(IXPathNavigable contextDocument, XmlResolver dataSources, XsltArgumentList argumentList, XmlWriter results)
at System.Xml.Xsl.XmlILCommand.Execute(IXPathNavigable contextDocument, XmlResolver dataSources, XsltArgumentList argumentList, TextWriter results)
at System.Xml.Xsl.XslCompiledTransform.Transform(IXPathNavigable input, XsltArgumentList arguments, TextWriter results)
at umbraco.presentation.webservices.codeEditorSave.SaveXslt(String fileName, String oldName, String fileContents, Boolean ignoreDebugging)