GDebi rejects a valid password

[fchampreux]

I just installed LMDE 64bits Cinnamon (201403 Cinnamon 64-bit).
I now try to install Oracle Virtualbox from the following file, downloaded from VirtualBox web site: virtualbox-4.3_4.3.20-96996~Debian~wheezy_amd64.deb
Double click on the file starts GDebi 0.9.1 which identifies the package version: 4.3_4.3.20-96996~Debian~wheezy and identifies 2 more packages to be installed (libqt4-network, libqt4-opengl)
I click on Install Package button, and GDebi asks for a password to grant for admin rights. The password I use is the correct one, given during installation, which works for sudo or Synaptic.
But GDebi keeps asking for the password, and raises a security error after 3 attempts.

Thanks for your help.

[nomko]

Did you used capitals in your password or typed the whole password in capitals?

[py-thon]

Did you at any time set a different password for root? After having done this you will have trouble because some programs ask for this password while others expect the first user's password set during installation. The pop-up window asking for the password is not clear as to which password is demanded.

[fchampreux]

Actually, it may not be Gdebi who rejects the password, but VirtualBox who rejects the version.
I used an agnostic version of VirtualBox, but now want to install the extensions.
I captured the following message :
Failed to install the Extension Pack /tmp/Oracle_VM_VirtualBox_Extension_Pack-4.3.20-96996-2.vbox-extpack.

The installer failed with exit code 1: glibtop: Non-standard uts for running kernel:

release 3.11-2-amd64=3.11.0 gives version code 199424.

Result Code: NS_ERROR_FAILURE (0x80004005)
Component: ExtPackManager
Interface: IExtPackManager {3295e6ce-b051-47b2-9514-2c588bfe7554}

Which is not clear to me !

Thanks for your help !