Cannot add e-books of any format in 0.8.60 (calibre freezes)

Updated from 0.8.58 to 0.8.60 on a Linux Mint 10 64bit box. (I know, I know, but I love this Linux Mint 10.) Calibre now freezes when I try to add any format e-book. Whether through the main interface or add format to existing entry through the edit metadata box. Ran calibre from CLI and got this error;

(process:18918): GLib-CRITICAL **: g_main_context_pop_thread_default: assertion `g_queue_peek_head (stack) == context' failed

I absolutely love calibre and feel it is THE most outstanding piece of open software available. Feel certain this will be resolved.

Thanks in advance.