The variable table name field is set at varchar 48 in the database description:
-- -- Table structure for table 'variable' -- CREATE TABLE variable ( name varchar(48) NOT NULL default '', value longtext NOT NULL, PRIMARY KEY (name) )
This is a problem if you're using CCK and Pathauto. I've found that I get weird errors with Pathauto because it is truncating the name as the value being passed in is greater than 48 chars. Increasing this to 64 worked for me.
I'm not sure if this should be mentioned on Pathauto or here, but it seemed like other modules could cause the same problem.