Code:
_LIT(KYourAppFullPath, "c:\\system\\apps\\yourapp\\yourapp.app");
_LIT(KYourAppParameters, "yourparam");
RFs fs;
User::LeaveIfError(fs.Connect());
CleanupClosePushL(fs);
TFindFile findFile(fs);
User::LeaveIfError(findFile.FindByDir(KYourAppFullPath,KNullDesC));
RApaLsSession ls;
User::LeaveIfError(ls.Connect());
CleanupClosePushL(ls);
CApaCommandLine *cmd = CApaCommandLine::NewLC();
cmd->SetLibraryNameL(findFile.File());
cmd->SetTailEndL(KYourAppParameters);
cmd->SetCommandL(EApaCommandRun);
User::LeaveIfError(ls.StartApp(*cmd));
CleanupStack::PopAndDestroy(3); // cmd, ls, fs