There is an option called RetLimit in BTEQ. You can specify the number of records that bteq can export.The maximum can be 2,147,483,407 records. So if you are exporting beyond the maximum limit I hope you will get the error.
Vinay is correct. A file with 34MM 97 byte rows is about 3GB. If you are exporting to Unix, there is a 2GB limitation within Unix. If you are exporting to Windows or MVS, you should have no problem going over 2GB.