apt-cache showing 2 records for the same package?

Question

I upgraded Parallels Plesk 10 yesterday using apt-get or aptitude. Now when I run apt-cache, there seems to be the same package (psa) installed twice with different versions! How is that possible and how do I fix that?

root@lvpsXXXXX:/opt/psa/admin/htdocs/skins/default/css# apt-cache show psa
Package: psa
Priority: extra
Section: non-free/net
Installed-Size: 556
Maintainer: Parallels <[email protected]>
Architecture: amd64
Version: 10.3.1-ubuntu10.04.build1012110718.16
Depends: plesk-core (>= 10.12.0), plesk-base (>= 10.12.0), psa-vhost, plesk-skins (>= 10.3.0), webalizer, pp-sitebuilder (>= 10.3.0), sw-engine (>= 2.2)
Conflicts: ppsmbe, psa-backup-manager (<< 10.12.0)
Filename: ../../PSA_10.3.1/dist-deb-Ubuntu-10.04-x86_64/base/psa_10.3.1-ubuntu10.04.build1012110718.16_amd64.deb
Size: 78270
MD5sum: c126e9f8102b1db26c5b076c0b8ef4f4
SHA1: 2e1877570b2eb35fb0930b795b9a37fa68f8dbeb
SHA256: 900d3d311d977f342324024404b51fd4d5b092dea28b0b286faaa55d704da446
Description: Parallels Panel v10.3.1 core files

Package: psa
Priority: extra
Section: non-free/net
Installed-Size: 548
Maintainer: Parallels <[email protected]>
Architecture: amd64
Version: 10.1.1-ubuntu10.04.build1010110120.18
Depends: plesk-core (>= 10.10.1), plesk-base (>= 10.10.1), psa-vhost, plesk-skins (>= 10.1.1), webalizer, pp-sitebuilder (>= 5.1.0)
Conflicts: ppsmbe, psa-backup-manager (<< 10.10.1)
Filename: ../../PSA_10.1.1/dist-deb-Ubuntu-10.04-x86_64/base/psa_10.1.1-ubuntu10.04.build1010110120.18_amd64.deb
Size: 77092
MD5sum: 3679b2b829140ee0e9ec933899b93b6a
SHA1: 7e95cf291dc9431ea0093cff4351d61440fa73df
SHA256: f3b9e6df7edb6b1a329f5e16585a5b96637d639eb2f99fb0499d0c3a4e08c6d4
Description: Parallels Panel v10.1.1 core files

Answer 1

apt-cache shows you what packages it knows about, not which packages you have installed. Try apt-cache policy psa to see which one is preferred, and dpkg -l psa to see what is actually installed.