Sharepoint 2007 / CRM 4 SOAP integration issue

We have a Sharepoint 2007 site which uses CRM 4 via SOAP for some custom functionality. Unfortunately the functionality has stopped working with the following errors:

Error 1:

Server was unable to process request.

at System.Web.Services.Protocols.SoapHttpClientProtocol.ReadResponse(SoapClientMessage message, WebResponse response, Stream responseStream, Boolean asyncCall) at System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(String methodName, Object[] parameters) at Microsoft.Crm.SdkTypeProxy.CrmService.Execute(Reque开发者_如何转开发st Request) at ECan.SharePoint.Web.Applications.MyECanUtilities.RefreshUserFromCrmQuery(CrmService crmService, QueryExpression query, Boolean& loginFound, Boolean& hasPermissionConsentCompliance, Boolean& hasPermissionWaterMeterForms)

Error 2:

Server was unable to process request.

at ECan.SharePoint.Web.Applications.MyECanUtilities.RefreshUserFromCrmQuery(CrmService crmService, QueryExpression query, Boolean& loginFound, Boolean& hasPermissionConsentCompliance, Boolean& hasPermissionWaterMeterForms) at ECan.SharePoint.Web.Applications.MyECanUtilities.RefreshUserFromCrm(String login)

All CRM integration code has been tested outside of Sharepoint on a development PC (not using Sharepoint) without any issue so I believe it must be a configuration issue with the live site.

Sharepoint is running on Windows Server 2008 Standard in case it's relevant.

The following config has been added to the system.web of the web.config file for the site:

<webServices>
  <protocols>
    <add name="HttpSoap" />
    <add name="HttpGet" />
    <add name="HttpPost" />
  </protocols>
</webServices>

Any ideas would be greatly appreciated.

Thanks in advance, Gavin