Mysql Innodb: InnoDB: ERROR: the age of the last checkpoint is InnoDB: which exceeds the log group capacity
At first glance, I would say that your innodb_log_file_size is way too small. It should be bigger to do two things:

Accommodate any big BLOB or TEXT fields
Holding bigger transactions

Here is what you should do for now to see if it helps:
STEP 01) Change the following in /etc/my.cnf
[mysqld]
innodb_log_buffer_size          = 32M
innodb_buffer_pool_size         = 3G
innodb_log_file_size            = 768M

STEP 02) service mysql stop
STEP 03) rm -f /var/lib/mysql/ib_logfile*
STEP 04) service mysql start
This will rebuild the following files

/var/lib/mysql/ib_logfile0
/var/lib/mysql/ib_logfile1

Give it a Try !!!
UPDATE 2013-07-03 12:37 EDT
I have updated my other posts on this and missed this one
ButtleButkus just commented at 2013-07-03 07:18:56 EDT

Wouldn't it be advisable to copy the ib_logfile* to another location for backup before deleting them?

Since there could be unfinished transactional data inside, here is what should be done
STEP 01) Change the following in /etc/my.cnf
[mysqld]
innodb_log_buffer_size          = 32M
innodb_buffer_pool_size         = 3G
innodb_log_file_size            = 768M

STEP 02) mysql -uroot -p -e&quot;SET GLOBAL innodb_fast_shutdown = 0;&quot;
STEP 03) service mysql stop
STEP 04) rm -f /var/lib/mysql/ib_logfile*
STEP 05) service mysql start
I added SET GLOBAL innodb_fast_shutdown = 0;. What does that do? It forces InnoDB to completely purge transactional changes from all of InnoDB moving parts, including the transactional logs (ib_logfile0, ib_logfile1). Thus, there is no need to backup the old ib_logfile0, ib_logfile1. If deleting them makes you nervous, then make Step 04
mv /var/lib/mysql/ib_logfile* ..

to put the old logs in /var/lib. If the recreation of the logs is successful and mysqld starts up, then you can delete the old logs.
I have been using this feature for a year now. I have updated my other posts to reflect this...

May 20, 2013 : Innodb one file per tablespace
May 05, 2013 : Issue after moving the ib_logfile1 and ib_logfile0 files
Jan 10, 2013 : Finding and fixing InnoDB index corruption
Dec 17, 2012 : MySQL Start/Stop
Feb 16, 2011 : How to safely change MySQL innodb variable &#39;innodb_log_file_size&#39;? (Last Update)
Feb 04, 2011 : MySQL InnoDB - innodb_file_per_table cons? (Last Update)
Oct 29, 2010 : Howto: Clean a mysql InnoDB storage engine? (Added as Step 03 on Jun 04, 2013)

If there are other older posts of mine where I do not mention innodb_fast_shutdown, let me know so I can update it. Thanks again, ButtleButkus.