PPS. On a long shot, you might want to see if this thread is relevant to you:
http://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&p=74632#74632 [sidefx.com]

PPPS. Try turning off your firewall and antivirus to see if it makes any difference just in case.

OK, forget my last few posts here.

Here's a series of steps to make everything better. I'm typing this out while I'm on Vista 32-bit. If there are any dialogs that come up asking whether you should allow the operation, allow them. This saves me lots of typing below.

1. From the Start Menu, right-click on Computer and choose Properties. Click on Advanced system settings. Click on Environment Variables. Under User variables, click New. For the Variable name, type in HOUDINI_DISABLE_CONSOLE and under Variable value, type in 1 and then click OK to close up all the dialogs.

2. Start up the License Administrator from the Start Menu. Choose File > Change License Server. Turn OFF Standalone Mode. Click on Accept, OK, and quit the program. Reboot.

3. Right-click on the Houdini shortcut icon on the desktop and choose Properties. Go to the Compatibility tab. Turn ON Run this program as an administrator.

4. Run Houdini by double-clicking on the icon. Wait for the icons to generate. Once the main interface starts up, IMMEDIATELY go to the main menu and turn OFF Edit > Open Help Browser at Startup. DO NOT CREATE ANY NODES. If you created any nodes, then you will have to kill Houdini from the Task Manager and repeat this step again. QUIT HOUDINI. THIS IS IMPORTANT SO THAT IT SAVES YOUR ICONS AND PREFERENCE.

Ok, at this point you should be able to double-click on Houdini as usual and NOT have to generate the icons upon every launch. You should also be able to create a Mantra ROP and render it. Although I've noticed that it does take like a full minute or two before mplay launches. I think the only way to solve this might be to run the Apprentice Licensing mode when you first installed Houdini.

Thanks edward, that worked like a charm for me. Change Licence Server was greyed out for me, but setting the environment variable and disabling the help browser check box seems to have done the trick

Nice work Edward. That finally did the trick.

Props to you.

I wish I had found this before, I should have looked harder… I just got it working on my 32bit XP machine. After buying a new graphics card and going through a lot of unnecessary annoyance its fixed. Anyway thanks, still got some work to do this will help .