Problem changing JNLP file association

Question

I installed SUN JRE 1.5 Update 7 in a fresh Windows XP machine and found the registry recongizes the JNLP file extension is associatied with it. Then I installed an application that downloads IBM WebSphere Application Client 6 which actually uses IBM JRE 1.4.2 . After this installation IBM JRE changes the .jnlp file association from Sun JRE 1.5.0_07 to its own 1.4.2 version.
Now I needed to change the JNLP file association back to previous one. I used Windows Explorer->Tool->Folder Options->File Types->Advanced->Edit and did that. However, I see my registry didn't change the association from IBM JRE to Sun JRE. But when I look at Java Control Panel, it says its associated with Sun JRE. Here is a windows shell script that I run to see the current JNLP file assocaition - which alwasy tells me its OBM JRE which is associated with the JNLP file extension. I tried restarting the machine, removing the cached copy from Java Control Panel without any difference.
Can you tell me when this file type association may not work and why? Is there any Windows Security Patch issue here? Also what are the registry keys that I should look for (a few are mentioned in the script below)?
code:
// To run it:
// CScript //Nologo JWS.js
var fso = new ActiveXObject("Scripting.FileSystemObject")
var gShell = new ActiveXObject("WScript.Shell")
function print(s) {
WScript.Echo(s)
function JavaSoft_JWS() {
var regKey = "HKLM\\SOFTWARE\\JavaSoft\\Java Web Start\\"
var ver = gShell.RegRead(regKey + "\\CurrentVersion")
var path = gShell.RegRead(regKey + "\\" + ver + "\\Home")
var javaws = path + "\\javaws.exe"
print("Sun JWS")
print("\tversion: " + ver)
print("\texe: " + javaws)
function IBM_JWS() {
var ver = "1.4.2"
var regKey = "HKLM\\SOFTWARE\\IBM\\Java Web Start v" + ver + "\\"
var path = gShell.RegRead(regKey + "\\" + ver + "\\Home")
var javaws = path + "\\javaws.exe"
print("IBM JWS for HKLM: ")
print("\tversion: " + ver)
print("\texe: " + javaws)
function JNLP_ASSOC_HKEY_LOCAL() {
var regKey = "HKEY_LOCAL_MACHINE\\SOFTWARE\\Classes\\JNLPFile\\Shell\\Open\\Command\\"
var path = gShell.RegRead(regKey)
var javaws = path + "\\javaws.exe"
print("HKEY LOCAL MACHINE Current JNLP File Association: ")
print("\texe: " + javaws)
function JNLP_assoc_HKCR() {
var regKey = "HKCR\\JNLPFile\\Shell\\Open\\Command\\"
var path = gShell.RegRead(regKey)
print("Current JNLPFIle association for HKCR:\t" + path)
function main(args) {
JNLP_ASSOC_HKEY_LOCAL()
JNLP_assoc_HKCR()
JavaSoft_JWS()
IBM_JWS()
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Answer 1

Did the clients happen to know what version they were upgrading from? We have seen this mostly when a system upgrades major Java versions, eg from 1.6 or 1.7 or switching from 32 to 64 bit Java and C:\Windows\System32\javaws.exe disappears or something silly.