Every time I try installing, It says I have one installed but I don't.

So Sims2Pack Clean Installer was uninstall from my computer and it probably wasn't uninstall correctly. I have Version 1.6.11 I believe and when I try to download a house it said "System.IO.FileNotFoundException: Could not load file or assembly 'Filetypes, Version=1.6.12.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The system cannot find the file specified.
File name: 'Filetypes, Version=1.6.12.0, Culture=neutral, PublicKeyToken=null'
at Sims2Pack_Installer.S2CPackage.ReadPackage(Bytes[] contents)
at Sims2Pack_Installer.S2CPackage.Complete(Bytes[] contents)
at Sims2Pack_Installer.S2Sims2Pack.RecognizeFiles()

WRN: Assemble binding logging is turned OFF.
To enable assembly bind failure logging, set the registry value
[HKLM\Software\Microsoft\Fusion!EnableLog] (DWORD) to 1
Note: There is some performance penalty associated with assembly bind failure
logging.
To turn this feature off, remove the registry value
[HKLM\Software\Microsoft\Fusion!EnableLog].

Please help me

Try this: http://www.modthesims.info/showthread.php?t=217787