[dll] The program can’t start because MSVCR71.dll is missing from your computer. Try reinstalling the program to fix this program

Here is the solution I found:

How to fix the missing MSVCR711.dll problem

You can find MSVCR71.dll file in following location of your installed SQL Developer 2.1 directory:

sqldeveloper-2.1.0.63.10\sqldeveloper\jdk\jre\bin\MSVCR71.dll