Thanks -- here's the messages that come up on Console when I open "Messages" and try to send something.
7/10/14 1:38:49.670 PM xpcd[159]: restored permissions (100600 -> 100700) on /Users/nattygsmith/Library/Containers/com.apple.iChat/Container.plist
7/10/14 1:38:59.514 PM com.apple.SecurityServer[15]: Session 100052 created
7/10/14 1:38:59.514 PM com.apple.SecurityServer[15]: Killing auth hosts
7/10/14 1:38:59.514 PM com.apple.SecurityServer[15]: Session 100051 destroyed
7/10/14 1:39:01.134 PM identityservicesd[2890]: [Warning] SQLITE_CORRUPT encountered error 11 while accessing /Users/nattygsmith/Library/IdentityServices/ids.db, exiting!
7/10/14 1:39:01.134 PM identityservicesd[2890]: [Warning] SQLite error in function: checkResultWithStatement message: database disk image is malformed sql: INSERT INTO outgoing_message (guid, account_guid, from_identifier, message_data, destinations, data_to_encrypt, encrypt_payload, use_top_level_dict, wants_response, timeout, command, wants_delivery_status, delivery_status_context, message_uuid, high_priority, date, is_sent) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?);
7/10/14 1:39:01.197 PM identityservicesd[2890]: [Warning] Database at path /Users/nattygsmith/Library/IdentityServices/ids.db is corrupt. Copying it to /var/folders/9m/p2255hxs0hz3n4bznj4yyp080000gn/T/ids.db.vngcjD for further investigation.
7/10/14 1:39:01.255 PM xpcproxy[2906]: assertion failed: 13E28: xpcproxy + 3438 [D559FC96-E6B1-363A-B850-C7AC9734F210]: 0x2
7/10/14 1:39:01.802 PM com.apple.launchd.peruser.501[147]: (com.apple.identityservicesd[2890]) Job appears to have crashed: Abort trap: 6
7/10/14 1:39:02.023 PM ReportCrash[2888]: Saved crash report for identityservicesd[2890] version 10.0 (1000) to /Users/nattygsmith/Library/Logs/DiagnosticReports/identityservicesd_2014-07-10- 133902_Nathaniels-MacBook-Air.crash
7/10/14 1:39:02.316 PM recentsd[462]: Failed to get Mail account information in a timely manner
7/10/14 1:39:03.375 PM identityservicesd[2907]: [Warning] SQLite error in function: CSDBSqliteStatementPerform message: outgoing_message.guid may not be NULL sql: UPDATE outgoing_message SET is_sent = 0
7/10/14 1:39:03.375 PM identityservicesd[2907]: [Warning] SQLite error in function: CSDBSqliteStatementReset message: outgoing_message.guid may not be NULL sql: UPDATE outgoing_message SET is_sent = 0