so i downloaded houdini aprentice on this computer and the family computer
on the family computer i had no troubles except that houdini started slow (bad computer XD)
so i tried it on this one and i get a error:
error installing key: LICENSE Generic houdini-master-noncommercial 9.0 1 16-jan-2008 +.+.+.+. (keeps going for a while)
unable to read/modify license file.
error: key installation failed

i searched around in the FAQ and they told me to do a manual install
but when i go to the license admin. i cant click on install licenses or manualy enter keys (they are greyed out)

i tried the command line tools (made a batch file with the key commands in it and ran it)
but still nog go
so any help? did i do something wrong?

PS hserver.exe is running so that couldnt be the problem
im running winxp SP2 32bit

I had this problem and solved it downloading the latest houdini 9.0 version and installing it.

but i allready have the latest version of houdini
il redownload it

then I supose you don't have the same problem as me.
I downloaded a 9.0.6XX version and done some tutorials. One day the license administrator shown me a problem with expired licenses, but apprentice licenses doesn't expire!! y donwloaded the latest houdini version ( 9.0.79X) and the problem disapeared.

i redownloaded and reinstalled it but still the same :s

Most likely the reason that the input fields are grayed out and you cannot enter the keys is the same that you get license installation error:

unable to read/modify license file.

You may need to log in as an Administrator to be able to modify certain files or keys in the registry. Otherwise, you can try looking for any errors or warnings in the diagnostic information which you can obtain from the License Administrator window in File > Diagnostic Information …

But, I suspect it really has to do with your user permissions, and logging in as an Administrator should fix the problem. (there may also be some read-only files that cause trouble, but I doubt that).

Rafal