How about a little more information. What version of FileMaker? Is it on Server? Is the table a native FileMaker table or ESS? If ESS, where is it from? Is the write ability off for the entire file or just that table? If it is the entire file, the file permissions may not have write access on the OS level. Have you tried it on another computer? Have you tested it on an account with [Full Access]? If not, it may be a FileMaker permissions issue.
When using multiple files or a data separation model, you need to very careful not to delete a TO (table occurance) which is the base table for some layout or scripted action in a file.
It sounds like you have a layout or script action which relies on a TO which is not longer in that file. If you have an OnCommit trigger script, check it as the most ikely place for a script step which needs repointing to the new/correct TO. If not that, go into layout mode and use the Manage Layouts menu (top of the layout list) to see if any of the layouts are missing a base table.
There are other possiblities, but all of them are likely to have to do with a missing TO (table occurance in the relationship graph).