The RSWebParts.cab file provided by Microsoft in the SQL Server 2012 SP1 Reporting Services Add-In For Sharepoint is broken. Its extracted file structure does not match its manifest or its INF file and so when you attempt to install it you received the dreaded "Failed to extract the cab file in the solution" error.
Is there a workaround to get this cabinet file working?
My workaround was to rebuild the cabinet file myself using the existing cabinet file and the working RSWebParts.cab file from a SSRS 2008 install.
.OPTION EXPLICIT ; Will Generate errors for mistakes
;.Set CompressionType=MSZIP ;** All files are compressed to cabinet files
.Set DiskDirectoryTemplate=CDROM;
.Set DiskDirectory1=;
.Set Cabinet=on
.Set CabinetNameTemplate=RSWebParts.cab
manifest.xml
report_explorer.gif
report_viewer.gif
RSWebParts.dll
RSWebParts.inf
RSWebParts.resources.dll
SPExplorer.dwp
SPViewer.dwp
.Set DestinationDir=de
de\RSWebParts.resources.dll
.Set DestinationDir=es
es\RSWebParts.resources.dll
.Set DestinationDir=fr
fr\RSWebParts.resources.dll
.Set DestinationDir=it
it\RSWebParts.resources.dll
.Set DestinationDir=ja
ja\RSWebParts.resources.dll
.Set DestinationDir=ko
ko\RSWebParts.resources.dll
.Set DestinationDir=pt
pt\RSWebParts.resources.dll
.Set DestinationDir=ru
ru\RSWebParts.resources.dll
.Set DestinationDir=zh-chs
zh-chs\RSWebParts.resources.dll
.Set DestinationDir=zh-cht
zh-cht\RSWebParts.resources.dll
Finally, open a Command Prompt and run makecab /f (your ddf location)
This will create an RSWebParts.cab file in the directory that is properly structured. Copy this to your Sharepoint server and install it per the instructions on MSDN.