It seems that maybe you have a large 'invisible' button that used to do something, like prevent anyone from clicking into thise fields. Hard to completely visualize your problem without a screen shot, but maybe you can try these ideas:
"..there is a large block (at least I see the four corner dots for it) covering the area that my fields are in.."
1. Can you drag that box off of the layout (it's not a tab or portal, right?)?
2. Or, with the 'box' handles showing, can you go to the inspector and click on (I can't think of the exact button name) the button that sends the object to the bottom?
3. Or, with the 'box' handles showing, what happens if you just click 'delete'?
It could also mean that the layout objects have been grouped and that they need to be ungrouped so that you can get to the individual button setup or script trigger settings on each field. If it's a group, you can click the group and then select "ungroup" from the arrange menu or the equivalent Icon on the Inspector's position tab.
Thank you for your attention to this most vexing issue. I did a "repair" install from the program disk. I can't be sure it helped, but I'm on another layout trying to get an unafected layout to copy to my original solution. I have a repeating field called" Item Quantity". which is just a text field for an invoice to enter the number of items ordered. When I enter a quantity it reports the "Script cannot be founmd or has been deleted" message, just like the other layout I had a problem with. I can find no script trigger or script button (hidden or otherwise). It had a larger than the 6 repeats showing when I clicked on it in layout mode. (it included the column title written above the actual field. I clicked on UNGROUP, which I did on the original box that prompted my question. It reduced my box size to just the field I wanted to highlight. I don't know how they got "grouped" in the first place, but that is another isuue. I'm enclosing an image, but it doesnt show anything that I think might help.
I will note that repeating fields are not the optimum design for an invoice--since FileMaker 3, a related table of line items and a portal make for a better option.
Script Triggers can be tricky to find. If you have FileMaker Advanced, enable the script trigger then do the steps that pop up this error message and you should see the needed info in the script debugger to see what trigger was tripped.
I suggest opening Layout Setup... and checking the script triggers tab there for any triggers. If one such as OnRecordCommit is specified, it might, in turn be attempting to perform a script that no longer exists in this file when the record is committed.