It means that your ink absorber is full. From a quick google search I am guessing you have a canon printer, and from canons web site it says this:
Press the Resume/Cancel button to clear the error.
Although printing is possible for a while, when the waste ink absorber (the waste ink tank) is full, printing is not possible.
Replacement of the waste ink absorber (the waste ink tank) is needed.
If it's not a canon please let us know.