I just solved my own connection issue with Oracle XE by running
SQL> ALTER SYSTEM SET DB_RECOVERY_FILE_DEST_SIZE=6294967296 SCOPE=BOTH;
the size of the C:\OracleFlash\XE\ARCHIVELOG had reached about 4gb, which was the old setting. now that I've fixed this problem, I'm wondering what I should do now (rather than just increasing the file size!). I'm fairly new to oracleXE, but familiar with sqlplus, etc. thanks!