I got a similar problem too, but recuva say the file is in excellent condition.
The file is about 3.5 gigabyte in size.
This is the error log Recuva gave me in debug mode:
-----------------------------------------------------------------
[2007-10-01 20:15:42] [iNFO ] Recuva v1.06.132
[2007-10-01 20:15:42] [iNFO ] System Info: MS Windows XP SP2, Intel Pentium 4 CPU 2.50GHz, 2,0GB RAM, Sapphire RADEON X1600 PRO
[2007-10-01 20:16:10] [iNFO ] OEM Name NTFS
[2007-10-01 20:16:10] [iNFO ] Reading MFT form 4
[2007-10-01 20:16:10] [iNFO ] Read from MFT: 47512 records total
[2007-10-01 20:16:10] [iNFO ] Boot sector: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=
[2007-10-01 20:16:10] [iNFO ] Reading up to 48652288 bytes at 0
[2007-10-01 20:16:10] [iNFO ] File record found (2)
[2007-10-01 20:16:10] [iNFO ] File record found (3)
[2007-10-01 20:16:10] [iNFO ] File record found (4)
[2007-10-01 20:16:10] [iNFO ] File record found (5)
[2007-10-01 20:16:10] [iNFO ] File record found (6)
[2007-10-01 20:16:10] [iNFO ] File record found (7)
[2007-10-01 20:16:10] [iNFO ] File record found (8)
[2007-10-01 20:16:10] [iNFO ] File record found (9)
[2007-10-01 20:16:10] [iNFO ] File record found (11)
[2007-10-01 20:16:10] [iNFO ] File record found (12)
[2007-10-01 20:16:15] [iNFO ] Reached the EOF
[2007-10-01 20:16:15] [iNFO ] Building folders
[2007-10-01 20:16:15] [iNFO ] Restoring tree
[2007-10-01 20:16:15] [iNFO ] Building file map
[2007-10-01 20:16:15] [iNFO ] Analyzing damage
[2007-10-01 20:16:16] [iNFO ] Returning list
[2007-10-01 20:16:56] [iNFO ] OEM Name NTFS
[2007-10-01 20:16:56] [iNFO ] Recovery has started
[2007-10-01 20:16:56] [iNFO ] Trying to recover C:\DOCUMENTS AND SETTINGS\ME\SKRIVEBORD\Dg1.iso
[2007-10-01 20:16:56] [iNFO ] File size is -778192896
[2007-10-01 20:16:56] [ERROR] bad allocation