DeleteDir doesn't work.

szDelPath = CommonAppDataFolder ^ "JetAdvice";
DeleteDir(szDelPath, ALLCONTENTS);

szDelPath = CommonAppDataFolder ^ "JetAdvice";
ChangeDirectory("C:");
LongPathToShortPath(szDelPath);
DeleteDir(szDelPath, ALLCONTENTS);

szDelPath = CommonAppDataFolder ^ "JetAdvice";
nResult = FindAllFiles( szDelPath, "*.*", szFilePath, RESET );
while ( 0 = nResult )
SetFileInfo( szFilePath, FILE_ATTRIBUTE, FILE_ATTR_NORMAL, "" );
nResult = FindAllFiles( szDelPath, "*.*", szFilePath, CONTINUE );
endwhile;

ChangeDirectory("C:");
LongPathToShortPath(szDelPath);
DeleteDir(szDelPath, ALLCONTENTS);