My first guess is that your Ingres transaction log has disappeared. Unfortunately if you are unfamiliar with Ingres, checking that is needlessly difficult.
Run a utility called cbf with no arguments. Highlight the line with Transaction Log and choose "Configure" from the menu at the bottom of the page. Note the file name of the log, then cd to the Primary Transaction Log location that is shown, then cd to ./ingres/log within it.
Look for the file name you noted, with a .l01 suffix. If you don't see it, that's your problem. Depending on how it disappeared it may be easy or hard to restore. DO NOT restore it from a backup. Call tech support for advice. They may just tell you to recreate it, which takes two minutes, or you may have a serious problem, with loss of committed transactions and data.