Unable to find valid Certification Path to Requested Target error received when launching tomcat web app via SSL

I am trying to quickly implement SSL ability into our existing Apache Tomcat 5.5.23 installation (JDK 1.5.0_12 as base) and have gotten reasonably far but have run into a bit of a wall.

I can navigate to https://www.sslhost.com/webapp/ and get the index page and it shows the proper SSL cert attached, but when I try to launch the application (Electronic Medical Record), I am getting the following error:

Error Sending POST: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target

Details
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[SOAPException: faultCode=Error Sending POST: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested targetURL:

I do not believe it is related directly to the EMR product but instead to perhaps the format of the cert I have from Network Solutions. I am using a PFX file for the keystore since this cert, so my server.xml looks like this:

    <Connector port="443" maxHttpHeaderSize="8192"
               maxThreads="150" minSpareThreads="25" maxSpareThreads="75"
               enableLookups="false" disableUploadTimeout="true"
               acceptCount="100" scheme="https" secure="true"
               clientAuth="false" sslProtocol="TLS" keystoreType="PKCS12" keystorePass="password" keystoreFile="C:\Program Files\Apache Software Foundation\Tomcat 5.5\unitypg.pfx" />

I believe the error has to do with the fact that the certificate we received from Network Solutions had 3 other certs along with it: AddTrustExternalCARoot.crt, UTNAddTrustServer_CA.crt and NetworkSolutions_CA.crt.  I ran the following commands to get these chain certs into the cacerts file (which I presume is what the error is complaining about, I'm new to this):

keytool -import -trustcacerts -alias root -file C:\SSLCerts\AddTrustExternalCARoot.crt -keystore "C:\Program Files\Java\jdk1.5.0_12\jre\lib\security\cacerts"

keytool -import -trustcacerts -alias INTER -file C:\SSLCerts\UTNAddTrustServer_CA.crt -keystore "C:\Program Files\Java\jdk1.5.0_12\jre\lib\security\cacerts"

where I ran into a problem perhaps is with the third cert&

keytool -import -trustcacerts -alias INTER2 -file C:\SSLCerts\NetworkSolutions_CA.crt -keystore "C:\Program Files\Java\jdk1.5.0_12\jre\lib\security\cacerts"

No where I could find mentioned three certs. Just a root and an INTER. So what is the extra cert?

Is it right to think this is what is causing my error?