Click on javascript:__doPostBack link in VB6

Here is the page URL that has a link in it I am trying to click on:

http://guggenheiminvestments.com/pro.../wfvk/holdings

I open this page in WebBrowser1.

The link within this page is:

javascript:__doPostBack('p$lt$zoneMainContent$pageplaceholder$pageplaceholder$lt$zoneCenter$ETFHoldi ngsWidget$Export','')

Here is the code I am using in VB6 that I am trying to use to click on the link (does not work):

WebBrowser1.Document.parentWindow.execScript "javascript:__doPostBack('p$lt$zoneMainContent$pageplaceholder$pageplaceholder$lt$zoneCenter$ETF Hold ingsWidget$Export','')"

I then need to save the page.

Help is appreciated. Thank you.