Thank you for your post.
I am unable to replicate the problem. This is what I did...
On a MacBook Pro running Mac OS X 10.6.4, I launched FileMaker Pro 11v2 and opened a database file that had many records. I turned on Instant Web Publishing. On an iPod touch running iOS 4.0.1, I launched Safari. I entered the local IP Address and the Instant Web Publishing page displayed. I selected the file and switched to Table View. I selected the second record, and it moved to the top and put me in Edit mode. After pressing Cancel, I then selected the fifth record. At first, the field highlighted, but nothing happened. I did it again with the same result. Finally, on the third attempt, the fifth record moved to the top and put me in Edit mode. This selection seemed a bit sporadic with other records.
I pressed the New Record icon (several times), and a new record was added immediately.
On an iPad, all buttons acted without any problems.
Let me know if your access privileges allow you to add a record.