Try again to install .ipk with tihis command:
opkg update && opkg install --force-overwrite /tmp/*.ipk
root@dm900:~# opkg update && opkg install --force-overwrite /tmp/*.ipk
Downloading https://feeds2.mynonpublic.com…m900/3rdparty/Packages.gz.
Updated source 'openatv-3rdparty'.
Downloading https://feeds2.mynonpublic.com/7.4/dm900/all/Packages.gz.
Updated source 'openatv-all'.
Downloading https://feeds2.mynonpublic.com…hf-neon-vfpv4/Packages.gz.
Updated source 'openatv-cortexa15hf-neon-vfpv4'.
Downloading https://feeds2.mynonpublic.com/7.4/dm900/dm900/Packages.gz.
Updated source 'openatv-dm900'.
Downloading https://feeds2.mynonpublic.com…m900_3rdparty/Packages.gz.
Updated source 'openatv-dm900_3rdparty'.
Downloading https://raw.githubusercontent.…feed/gh-pages/Packages.gz.
Updated source 'enigma2-settings-feed'.
Downloading https://raw.githubusercontent.…feed/gh-pages/Packages.gz.
Updated source 'oe-alliance-picon-feed'.
Downloading https://feeds2.mynonpublic.com…hf-neon-vfpv4/Packages.gz.
Updated source 'openatv-static-cortexa15hf-neon-vfpv4'.
Downloading https://feeds2.mynonpublic.com…/static-dm900/Packages.gz.
Updated source 'openatv-static-dm900'.
Refusing to load file '/tmp/enigma2-plugin-extensions-multi-stalkerpro_1.1+git32+9369df00+9369df017f-r0_cortexa15hf-neon-vfpv4.ipk' as it matches the installed version of enigma2-plugin-extensions-multi-stalkerpro (1.1+git32+9369df00+9369df017f-r0).
Unknown package '/tmp/enigma2-plugin-extensions-multi-stalkerpro_1.1+git32+9369df00+9369df017f-r0_cortexa15hf-neon-vfpv4.ipk'.
* opkg_solver_install: Cannot install package /tmp/enigma2-plugin-extensions-multi-stalkerpro_1.1+git32+9369df00+9369df017f-r0_cortexa15hf-neon-vfpv4.ipk.
root@dm900:~#