I\'ve just installed SQL Developer 4.1.1 64-bit on a Windows Vista machine, in directory c:\\sqldeveloper.
c:\\sqldeveloper
My Java installation is in c:\\program
c:\\program
You need to copy the msvcr100.dll file from sqldeveloper/jdk/jre/bin/msvcr100.dll to sqldeveloper/sqldeveloper/bin/. Then just open SQL Developer again.
msvcr100.dll
sqldeveloper/jdk/jre/bin/msvcr100.dll
sqldeveloper/sqldeveloper/bin/