Welcome to EvC, sean.
In an AIG DVD called The Code of Life Dr. Georgia Purdom said that all point mutations that have been studied on the molecular level turn out to reduce the genetic information and not to increase it.
AIG -- like most creationist organisations -- is a Christian propaganda vessel, not a scientific institution. I would basically ignore anything they say about evolution or cosmology as a rule of thumb, because they simply don't know what they are talking about.
Fortunately, you've happened across a rather more informed group here and I'm sure many will pop in to discuss the question you raised (before subsequently going off tangentially on barely related points
)
But anyway, to topic at hand:
Is this true and does it pose any problem for evolution?
No, it is not true. More later.
Whether or not it would pose a problem is a debatable issue, but effectively a pointless one.
So about the issue of whether mutations cannot increase information.
Say generation 1 of a population has as part of their genetic makeup a string
alpha of the bases GACGATGC.
Then some descendants of generation 2 inherit this string, but with mutations. The rest of the descendants don't get mutations there and have the original string.
In their genes are now the strings are say,
beta GAC
TTTGC and
gamma GACGAT
AC (mutated parts are in bold; labels of strings are italicised).
Now, there may be more mutations to this string in the next descendants, or the descendants may simply inherit the string their parents in generation 2 had.
Your only possible string before these mutations was
alpha, but now you have the possible strings
alpha and
beta and
gamma. Which set contains more options, and hence more information?
Hint: it's not what AIG would have said.
*Bear in mind that this is a very simple demonstration. It does not factor in the possible indels (which would also alter the amount of "information") nor does it account for the process of turning DNA into protein (where using different bases might make no difference anyway or could substantially change the protein).