Are you using v3.0.3? What does your Service Suspension email template look like for HTML/text content?
If you're running v3.0.3, did you make sure to run the upgrade afterward? /admin/upgrade/
It sounds like you may not have actually run the upgrade, in which case that email template was never updated. If that's the case, then your error is caused by the placeholder content that existed previously, and which contained an invalid comparison operator "=", instead of "==". You'd need to run the upgrade.