BB Software :: Configuring Messaging And Gmail Bounce-back?

I thought i set things up right in making my Gmail account the primary one that my BB uses to send/receive mail. On the main menu
there is the icon of the mail folder, and the similar looking one with the small Globe next to it. Both folders appear to receive identical messaging. On my prior Sanyo handset with Sprint, I just used a standalone Gmail-Mobile app. and didn't do any 'push' type configuration...which would be fine for me with the BB. Is there some reason that there are essentially 'two mail folders' or can i eliminate that situation? Also, I use this gmail account as a sort of catch-all for my business's domain email address - i simply have that one set to Forward to Gmail. So, if I send from my 'regular (mail@domain.com) i will typically get a reply to both my regular DN email box, as well as a forwarded one to the Gmail inbox.... However, since assiging Gmail to my BB, i've found that i get random bouncebacks on my email clients on my office and studio computers when i send to certain recipients whom i routinely send stuff to. I can't help thinking it's something to do with the BB.It seemed more prevalent when i was using the Gmail Mobile app on the BB, so i stopped using that- and now just get the Gmail on the BB as my mail account. how to clean this up and is there any known issue about using Gmail Mobile app. - Like, if i wanted to deactivate it as my BB mail account, shouldn't i be able to just use the standalone app. for my email access or...am i missing something?