In order to fix the issues, press Windows + Pause/Break key combination and click the Change Settings button below Windows logo. Select the Advanced tab, click the Settings button below Performance, navigate to the Data Execution Prevention tab and check the Turn on DEP for all programs and services except those I select box. After that, press Add, navigate to the Pokemon Darkflame installation folder, select the game and press the Apply button. If this doesn't help, remove the game from your computer (Control Panel > Uninstall a program), run CCleaner and install it again.