[SOLVED {sort of}] Can't upgrade to VM 3.6.4

[WebStuff]

Trying to upgrade 4 sites at the moment but none will work.
All have this error, they will download a zip file to tmp but it is only 6.6kB and corrupted/un-openable.

Current VM 3.6.2
Joomla 3.9.2
All paths are set and writable in the configuration section of both Joomla and VM
PHP 7.2

[WebStuff]

Managed to download the update directly. Then installed by drag drop in admin. I'll mark this as solved but still would love to know why I can't update via backend normal update.

[StefanSTS]

Hm, I never use the automatic update.

And I never update the first day VM is released.

But I could try on a test, hm, yes, the AIO gives me this.
0 Call to a member function load() on null

So I recommend, not using the automatic installer. It's never a good feeling doing that with VirtueMart.

[jenkinhill]

0 Call to a member function load() on null

On my testing site I installed com_virtuemart.3.6.4.10187_package_or_extract.zip by drag 'n drop (as is my habit when installing any extension these days) and did not see any error message. All hunky dory.

[Milbo]

The error was only using the joomla updater. It was my fault. Last time some testers mentioned that they got directly the package. It would be nice, that if someone wants to update the AIO, that it directly downloades always the package. so it could not happen, that people do not update the AIO, or the AIO first and stuff like that. But somehow the joomla installer notices, that I give him the package and not just the installer. But I tested the package, the package itself is okey. I changed hte update xmls now and so it works. I tested it.

[diri]

Milbo, I'm sorry but:

Joomla 3.9.12 edit: PHP 7.2.24

Two independant systems.

System1:
Joomla shows 2 updates available in BE's control center after login.
Going to Extensions -> manage -> install to install component and aio manually shows an empty screen (nothing installed so far).
No chance to perform an action.

System 2:
Joomla shows updates available like system 1.
"Show updates" displays component and aio.
Selected component to install all looked fine at very first moment - vm installed component 3.6.4 10187.
Selecting aio it started update as well but an errormessage "0 ..." appeared.
Same as above:
Joomla backend looks damaged, no installation screen in backend.

[Milbo]

"Selecting aio it started update as well but an errormessage "0 ..." appeared."

What means that?

[diri]

See message from Stefan above:

0 Call to a member function load() on null

[StefanSTS]

That problem is solved and works now.