FTP never completes with IIS

I am running WordPress Multisite on Windows Azure Web Sites. Windows Azure runs IIS and so far everything has worked smoothly, except BackWPup. I have tried email, Windows Azure Storage, and FTP. Currently FTP is the most successful, however the FTP upload always fails to complete. It gets to around 24%. It looks like the plugin thinks it is still uploading, however the percentage never moves and the file size never changes. I have a feeling the issue may lie with IIS. Is there any guidance for running on IIS? Perhaps solving this issue will also fix the Windows Azure Storage issue, which is the backup storage location I would prefer to use.

Website running on IIS with Windows Azure
FTP server running pureFTPd on Linux at MediaTemple

Here is a dump of one of the log files:

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[INFO] BackWPup version 3.0.6; WordPress version 3.5.1; A project of Inpsyde GmbH developed by Daniel Hüsken [INFO] This program comes with ABSOLUTELY NO WARRANTY. This is free software, and you are welcome to redistribute it under certain conditions. [INFO] BackWPup job: Full Backup; DBDUMP+FILE+WPPLUGIN [INFO] BackWPup job started manually [INFO] PHP ver.: 5.4.9; cgi-fcgi; WINNT [INFO] Maximum script execution time is 300 seconds [INFO] MySQL ver.: 5.5.21-log [INFO] curl ver.: 7.27.0; OpenSSL/0.9.8x [INFO] Temp folder is: C:/DWASFiles/Sites/msopentech/VirtualDirectory0/site/wwwroot/wp-content/uploads/backwpup-98372-temp/ [INFO] Logfile folder is: C:/DWASFiles/Sites/msopentech/VirtualDirectory0/site/wwwroot/wp-content/uploads/backwpup-a6fdb-logs/ [INFO] Backup type is: archive [INFO] Backup file is: C:/DWASFiles/Sites/msopentech/VirtualDirectory0/site/wwwroot/wp-content/uploads/backwpup-98372-temp/backwpup_7140e9_2013-03-26_18-09-50.tar.gz [26-Mar-2013 18:09:50] 1. Try to dump database … [26-Mar-2013 18:09:50] Connected to database msopentechweb3 on us-cdbr-azure-c-west-109.cleardb.com [26-Mar-2013 18:09:50] Dump database table "owa_action_fact" [26-Mar-2013 18:09:50] Dump database table "owa_ad_dim" [26-Mar-2013 18:09:50] Dump database table "owa_campaign_dim" [26-Mar-2013 18:09:50] Dump database table "owa_click" [26-Mar-2013 18:09:50] Dump database table "owa_commerce_line_item_fact" [26-Mar-2013 18:09:50] Dump database table "owa_commerce_transaction_fact" [26-Mar-2013 18:09:50] Dump database table "owa_configuration" [26-Mar-2013 18:09:50] Dump database table "owa_document" [26-Mar-2013 18:09:50] Dump database table "owa_domstream" [26-Mar-2013 18:09:50] Dump database table "owa_exit" [26-Mar-2013 18:09:50] Dump database table "owa_feed_request" [26-Mar-2013 18:09:50] Dump database table "owa_host" [26-Mar-2013 18:09:50] Dump database table "owa_impression" [26-Mar-2013 18:09:50] Dump database table "owa_location_dim" [26-Mar-2013 18:09:50] Dump database table "owa_os" [26-Mar-2013 18:09:50] Dump database table "owa_queue_item" [26-Mar-2013 18:09:50] Dump database table "owa_referer" [26-Mar-2013 18:09:50] Dump database table "owa_request" [26-Mar-2013 18:09:50] Dump database table "owa_search_term_dim" [26-Mar-2013 18:09:50] Dump database table "owa_session" [26-Mar-2013 18:09:50] Dump database table "owa_site" [26-Mar-2013 18:09:50] Dump database table "owa_site_user" [26-Mar-2013 18:09:50] Dump database table "owa_source_dim" [26-Mar-2013 18:09:50] Dump database table "owa_ua" [26-Mar-2013 18:09:50] Dump database table "owa_user" [26-Mar-2013 18:09:50] Dump database table "owa_visitor" [26-Mar-2013 18:09:50] Added database dump "msopentechweb3.sql" with 52.22 kB to backup file list [26-Mar-2013 18:09:50] Database dump done! [26-Mar-2013 18:09:50] 1. Trying to make a list of folders to back up … [26-Mar-2013 18:10:10] WARNING: opendir(C:/DWASFiles/Sites/msopentech/VirtualDirectory0/site/wwwroot//sites/,C:/DWASFiles/Sites/msopentech/VirtualDirectory0/site/wwwroot//sites/): The system cannot find the file specified. (code: 2) [26-Mar-2013 18:10:10] WARNING: opendir(C:/DWASFiles/Sites/msopentech/VirtualDirectory0/site/wwwroot//sites/): failed to open dir: No such file or directory [26-Mar-2013 18:10:10] 706 folders to back up. [26-Mar-2013 18:10:10] 1. Trying to generate a file with installed plugin names … [26-Mar-2013 18:10:12] Added plugin list file "network-base.pluginlist.2013-03-26.txt" with 4.32 kB to backup file list. [26-Mar-2013 18:10:12] 1. Trying to create backup archive … [26-Mar-2013 18:10:12] Compression method is TarGz [26-Mar-2013 18:11:45] Backup archive created. [26-Mar-2013 18:11:45] Archive size is 28.64 MB. [26-Mar-2013 18:11:45] 4095 Files with 60.57 MB in Archive. [26-Mar-2013 18:11:45] 1. Try to send backup file to an FTP server … [26-Mar-2013 18:11:45] Connected to FTP server: msot.sirgecko.com:21 [26-Mar-2013 18:11:45] FTP client command: USER azure@msot.sirgecko.com [26-Mar-2013 18:11:45] FTP server response: User azure@msot.sirgecko.com logged in. [26-Mar-2013 18:11:45] FTP client command: SYST [26-Mar-2013 18:11:45] FTP server reply: UNIX [26-Mar-2013 18:11:45] FTP current folder is: /network-base/ [26-Mar-2013 18:11:45] FTP client command: PASV [26-Mar-2013 18:11:45] FTP server reply: Entering passive mode [26-Mar-2013 18:11:45] Starting upload to FTP  … [26-Mar-2013 18:27:12] ERROR: Aborted by user!

http://wordpress.org/extend/plugins/backwpup/