Internet Stalling

I have been having some internet connectivity issues and am wondering if it is an Avast issue. The problem is that suddenly, all web browsers will have loading issues. The loading circle or progress bar, depending on the browser, will spin or stall respectively, obviously making no progress. A few minutes later, the browsers will seemingly regain their connections and proceed to load all pages at the usual fast speeds. Other computers on the same network are able to load pages quickly as usual while the Mac is stalling. The Mac is connected by wired ethernet, making physical connection issues unlikely.

These lines appeared in my console the last time I experienced the issue:
com.avast.proxy[127]: Error connecting to server: Connection refused
com.avast.proxy[127]: Error connecting to server: connect(): Address family not supported by protocol family

The following line appears in my console approximately 40 times per hour:
com.avast.proxy[121]: Error reading receive buffer: read(): Connection reset by peer

These lines appear randomly and rather frequently in the console:
com.avast.proxy[127]: Defective HTTP request!
com.avast.proxy[127]: Defective HTTP response!
com.avast.proxy[127]: Error connecting to server: connect(): No route to host

I also randomly get gibberish from Avast in the console. For example:
com.avast.proxy[127]: ��� �ߍ2Ϯ�n���d���8���>
com.avast.proxy[127]: ���I�,�d�a�:�}�’�&�p?$�
com.avast.proxy[127]: ��+ �!&�^}x�Bwe�+2?e-
com.avast.proxy[127]: ��0�p�]E�zY�#�I8
com.avast.proxy[127]: ��L�V�t�{�9�%�%�8�~�o�|?
com.avast.proxy[127]: �����Ɂ�ø�睽���䋱�?��
com.avast.proxy[127]: ���b���S�ް؀� ҝ�S��?S�

I read that having IPv6 enabled in the shields could cause issues. (I do not have IPv6 on my connection.) I disabled IPv6 in the preferences for both the web and mail shields. My issues still occur. I know that Avast might not be the cause of my issue, but considering these console messages, it seems worth investigating.

Running OS X 10.8.5 and Avast 8

When the stalling issue occurs, I remain able to ping sites using the terminal. My suspicion is further raised.

As it turns out, I uninstalled Avast and have not had a single stall since.