Adding a registry key in windows with quotes needed in the data using a batch script

Use backslashes to escape the inner quotes, i.e.:

reg add "HKEY_LOCAL_MACHINE\Software\Classes\jarfile\shell\open\command" /v "" /t REG_EXPAND_SZ /d "\"C:\Program Files\Java\jre7\bin\javaw.exe\" -jar \"%1\" %*" /f

Percent literals must be doubled in a batch file: \"%%1\" %%*"

as an addition to dbenham's answer, you should use backslaches and quotes for location path !!
(i mean, you should use "\"C:\Program Files..... instead of "C:\Program Files..... )

so this is the final answer for typical percent sign & adding problem:

reg add "HKEY_LOCAL_MACHINE\Software\Classes\jarfile\shell\open\command" /v "" /t REG_EXPAND_SZ /d "\"C:\Program Files\Java\jre7\bin\javaw.exe\" -jar \"%%1\"" /f

thanks dbenham!