Argument 'Start' must be greater than zero.

Can you post a snippet of the source XML you are using?

t><amount currency="GBP">0.13</amount></payment></commission_entitlement><tpsdata><exweb_varied varied_name="Sum Assured"><original_value>50000</original_value><new_value>50000</new_value></exweb_varied><exweb_varied varied_name="Term"><original_value>15</original_value><new_value>15</new_value></exweb_varied></tpsdata></client_specific_illustration><tpsdata><exchange_formid></exchange_formid><exchange_extranet_available>False</exchange_extranet_available><print_types_available>99</print_types_available></tpsdata></product></application></m_content></message></transaction></m_content></message>
<message xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns="http://www.origoservices.com"><m_control><control_timestamp>2010-12-06T09:16:33.0253</control_timestamp><message_id>306f443f-61e5-4c39-a8ef-8f3a6c15a3df</message_id><retry_number>0</retry_number><message_type>Remote Publishing Alert</message_type><message_version>/origo/2.1/RPAlert.xsd</message_version><expected_response_type>none</expected_response_type><initiator_id>Exchange, The</initiator_id><initiator_orchestration_id>338763_010995_91_GL</initiator_orchestration_id><responder_id>LPDirect</responder_id></m_control><m_content><alert_action>Add</alert_action><target_environment>Live</target_environment><transaction originator_ID="AEGON Scottish Equitable"><message xmlns="http://www.origoservices.com" schemaLocation="http://www.origoservices.com/Schema/3_2/QNBProtectionQuoteResponse.xsd"><m_control><control_timestamp>2010-12-06T09:16:19.0000</control_timestamp><message_id>ce6710dd-9471-41c2-ac5f-
073a093ceac7</message_id><retry_number>0</retry_number><message_type>Quotation Response</message_type><message_version>/origo/3.2/QNBProtectionQuoteResponse.xsd</message_version><message_status>Success</message_status><response_location>TQ-Quotes-Web-Service~B8D30C30</response_location><initiator_id>LPDirect</initiator_id><initiator_orchestration_id>219_302176_6292056</initiator_orchestration_id><user_id>LPD001 LPD002</user_id><responder_id>Exchange, The</responder_id></m_control><m_content><b_control><service_provider_reference_number>338763</service_provider_reference_number><intermediary_case_reference_number>010120609162165</intermediary_case_reference_number><quote_type>Comparison</quote_type><quote_or_print>Quote Only</quote_or_print><generic_quote_ind>No</generic_quote_ind><message_version_number>3.2</message_version_number><submission_date>2010-12-06</submission_date><quote_response_status>Warning</quote_response_status></b_control><intermediary type="IFA"><sib_number>150427</sib_number><company_name>L
ife Policies Direct</company_name><branch_name>Life Policies Direct</branch_name><agency_address><postcode>WV3 0TZ</postcode></agency_address><contact_details><name>LPD001</name></contact_details></intermediary><application><personal_client id="pc1"><title>Mr</title><forenames>Lewis</forenames><surname>Turner</surname><sex>Male</sex><date_of_birth>1989-04-11</date_of_birth><tax_rate>20</tax_rate><smoker_ind>No</smoker_ind><preferred_life_ind>No</preferred_life_ind></personal_client><product type="Term Protection" product_code="Electronic"><product_name>Term Assurance (e)</product_name><increment_ind>No</increment_ind><benefits_required><life_assured personal_client_id="pc1" sequence_number="1"></life_assured><death_ind>Yes</death_ind><death_or_earlier_cic_ind>No</death_or_earlier_cic_ind><critical_illness_ind>No</critical_illness_ind><tpd_ind>No</tpd_ind><waiver_ind>No</waiver_ind><unemployment_ind>No</unemployment_ind></benefits_required><quote_details><reference_number></reference_number></quote_details><ris
k_benefit id="rb1" type="Life And Health"><cover_basis>

http://publib.boulder.ibm.com/infocenter/iseries/v7r1m0/index.jsp?topic=/rzash/srchz_xmlsearch.htm

http://social.msdn.microsoft.com/forums/en-US/winforms/thread/278276bf-5226-46b4-921d-8c5f62cf6c06

Dim n as integer= InStr(strXml, "<exweb_varied varied_name=""Term"">")
If n>0 Then
   XmlSearch = Strings.Mid(strXml, n)
Else
   MsgBox("Not found!")
End If