Rapi.dll is a file used by Windows 7 to help control various remote access features on your system. Notably used by the "ActiveSync" program, as well as various mobile phone software packages, the rapi.dll file is part of the core Windows functionality. Unfortunately, it's also a big cause of problems for Windows as since it needs to read the rapi.dll file so much, any problems with it will have drastic consequences. Fortunately, there's an easy way to fix any rapi.dll errors that you'll find on your PC, especially if you're using Windows 7.
The errors which rapi.dll causes include the likes of "rapi.dll not found" and "rapi.dll unable to be located". If you're seeing these errors, it generally means that there's either a problem with the file itself or with the settings / software trying to use the file. In order to fix the problem, you basically need to repair the various issues which are causing it to show, which will include the likes of updating Windows as well as fixing the file's location & any other errors it may have.
The way to fix the rapi.dll error on your PC is to first make sure that your PC is up to date. The errors you're seeing could well be caused by a general bug / problem in the Windows system, which will be corrected with an update. You can update your PC by using the Windows Update program in Start> All Programs> Windows Update. Along side this, you should also make sure that rapi.dll is located in the C: Windows System32 folder of your PC (the folder where all DLL files are kept for your system). If you do not have the file on your PC, you should download it from the Internet and then place it in that folder.
It's also recommended that you use a 'registry cleaner' program to fix any errors that your system has with the "Registry Database" of your PC. This is a central storage database for all the files and settings your system uses to run, and is used continuously to help your PC recall the likes of your desktop wallpaper, latest emails and even your most recent emails. The registry is also home to a large list of DLL files on your PC, which your system will use to read all the files it needs to run. Unfortunately, this list of files often gets damaged & corrupted, leading your system to run much less reliably. To fix this issue, you should look to use a registry cleaner tool to repair all the problems you may have on your system. These software tools can be downloaded from the Internet and installed on your PC to help clean out the errors you're seeing.