Quelle: http://bigsnowball.com/content/fixing-sqldeveloper-msvcr71dll-not-found-error

To fix it, properly, you need to install SQLDeveloper yourself. Fortunately, this is simple.

• Run regedit as the Administrator
• Expand HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionApp Paths
• Add a new Key to App Paths called sqldeveloper.exe
• Set the (Default) value to the full path to the executable (including the executable name).
• Create a new String value for sqldeveloper.exe called Path and set its value to the jre / bin folder in the SQLDeveloper files.

And here’s what it looks like: