Do you just need to change this

sEnv = sEnv & "<urn:dataXml><=!=[=C=D=A=T=A=[<KnSubject xmlns:xsi=""w3 schema instance link""><Element><Fields Action=""insert""><StId>86</StId><Ds> onderwerp.value </Ds><SbPa> ""c:\"" & bestand.value "".pdf"" </SbPa><FileTrans>True</FileTrans></Fields><Objects><KnSubjectLink><Element SbId=""""><Fields Action=""insert""><SfTp>2</SfTp><SfId> nummer.value </SfId><ToEM>True</ToEM></Fields></Element></KnSubjectLink></Objects></Element></KnSubject>]=]=></urn:dataXml>"
to this

sEnv = sEnv & "<urn:dataXml><=!=[=C=D=A=T=A=[<KnSubject xmlns:xsi=""w3 schema instance link""><Element><Fields Action=""insert""><StId>86</StId><Ds> " & onderwerp.value & " </Ds><SbPa> ""c:\""" & bestand.value & """.pdf"" </SbPa><FileTrans>True</FileTrans></Fields><Objects><KnSubjectLink><Element SbId=""""><Fields Action=""insert""><SfTp>2</SfTp><SfId> " & nummer.value & " </SfId><ToEM>True</ToEM></Fields></Element></KnSubjectLink></Objects></Element></KnSubject>]=]=></urn:dataXml>"