As with umask, fmask and dmask are subtracted from 777 to get you the effective permitions. So you are actually mounting your share as 000, meaning "no one can read, write or execute"
Also, do you really need that many custom configuration options? If this is your home computer, I suggest this:
//IomegaStorCenter/public/Server /home/jmm/Iomega cifs defaults,uid=jmm,gid=plugdev,umask=022
jmm, I presume, is your username. If not, change accordingly. Also, I strongly suggest you not to mount drives in your home directory. As root, create /mnt/iomega directory and then mount there. If you want, create a symlink in your home folder pointing there. The command in terminal would be:
sudo mkdir -p /mnt/iomega
And the fstab entry would then be:
//IomegaStorCenter/public/Server /mnt/iomega cifs defaults,rw
Troubleshoot
If this didn't work, let's try from the very beggining, just to check if there are any loose ends:
1 - Delete all lines from fstab concerning the IomegaStorCenter. Reboot
2 - Use Nautilus > Network > Windows Network > Workgroup (or whatever your workgroup is called), and see if the drive shows. Double-click it.
3 - Does it ask for username/password? Do you know them? Do they work and nautilis show the shared folders? (note: this is not your Ubuntu username/password.It's the share login/password, which you might have previously configuted in IomegaStorCenter
4 - Stil using nautilus, can you drag and drop and create files there? Edit them, rename, delete, etc?
If yes, then fstab is your only issue. If not, then you must configure IomegaStorCenter before going on, until you can properly access it via Nautilus.
5 - Unmount the drive in Nautilus (use the "Eject" button)
Now in terminal (it can be done via GUI/Nautilus, but copy-and-paste command in terminal is faster and less error-prone):
6 - delete the old mountpoint. MAKE SURE IT IS EMPTY BEFORE YOU DO THAT
rmdir /home/jmm/Iomega
7 - create the new mountpoint and a symlink from old location to the new one
sudo mkdir -p /mnt/iomega
ln -s /mnt/iomega /home/jmm/Iomega
8 - Add one (but not both) of these lines to fstab, depending on whether your share needs password or not:
//IomegaStorCenter/public/Server /mnt/iomega cifs defaults,rw,username=YOURSHAREUSER,password=YOURPASSWORD 0 0
//IomegaStorCenter/public/Server /mnt/iomega cifs defaults,rw 0 0
9 - Mount it, to test if enty is ok:
sudo mount /mnt/iomega
10 - Open nautilus, got to /mnt/iomega and try to copy some files. Edit, delete, etc.
If it works, great. If not, try to copy files using terminal and paste here the error message. also type ls -la /mnt/iomega, sudo mount and paste results.
11 - Now go to Wine config and make sure D: points to the new, correct location, /mnt/iomega. Also use nautilus to browse to /home/jmm/.wine/dosdevices/d: and see if it the correct location.
12 - Test you VB app and be happy :)