Dumb question, but is it possible some data needs to be sanitized, like you're getting something in the string that's whacking the connection itself? Unlikely but not impossible. Once had a Windows program which allowed input without, er, much sanitizing, and a customer sending "X00" would kill the data stream.
Unlikely, but the Internets say:
The source of an ORA-03113 is a broken connection between Client and Server process, a blanket end-of-file on a communication channel error.
...so it seems worthy to rule out?
Listen. Strange women lying in ponds distributing swords is no basis for a system of government. Supreme executive power derives from a mandate from the masses, not from some farcical aquatic ceremony. You can't expect to wield supreme executive power just 'cause some watery tart threw a sword at you! I mean, if I went 'round saying I was an emperor just because some moistened bint had lobbed a scimitar at me, they'd put me away!