Limit on number of entries?

[JUNIPER]

    Returning home from vacation I started entering my credit card 
transactions. After entering several with no problem, when I filled in 
the columns for another charge and hit "enter", nothing happened. It did 
not enter the transaction and move to the next, blank, line to proceed.
    I tried deleting the entry and re-entering it. Same thing. I tried 
deleting the previous entry and re-entering that one and it worked fine, 
as always, but still won't take the next one (I also tried using other 
data for the next one, with the same negative result). It is as if there 
is a maximum number of entries that I am allowed - could that be the 
case??? I have about 210 credit card charges entered in that account. It 
is like I am up against some kind of wall. Everything else seems to be 
working fine.
    GnuCash 1.8.11 Red Hat Fedora
    Steve Juniper