It looks like the table object is recognized as it does note that there is a problem with a particular column. However, the error seems to indicate that the column in question contains data of a data type not recognized for storing the value in the table checkpoint. As mentioned, using Object Spy may help to figure out what is going on here, to examine the cell in question to see what the data type is in that column and determine why it's failing.
The alternative to using the built in checkpoint is to traverse the table manually, using a for loop and checking the values in the application against variable of the "Table" type.