If you notice your HTC device crashing periodically, it is due to a combination of the text message language, OS version and software. It is more likely to happen with messages written in languages with Devanagari characters, such as, but not limited to: Hindi, Marathi, Nepali, Kashmiri and Punjabi. The problem is also likely to broadly effect devices running on Android 4.0.3 and 4.0.4.
This problem should have been fixed by the latest HTC software update. Please check if you have a software update available for your device by going to Settings > About > Software Update. If you do not have any software update available, please contact your provider.