Could you elaborate please? Does prepare returns undef? Does execute returns undef? Does fetch returns undef? Does fetch return the wrong number of columns? Does your computer go up in flames? What's in $DBI::errstr?

Update: The DBI docs have a little to say on the subject:

Handling BLOB / LONG / Memo Fields

Many databases support ``blob'' (binary large objects), ``long'', or similar datatypes for holding very long strings or large amounts of binary data in a single field. Some databases support variable length long values over 2,000,000,000 bytes in length.

Since values of that size can't usually be held in memory, and because databases can't usually know in advance the length of the longest long that will be returned from a SELECT statement (unlike other data types), some special handling is required.

In this situation, the value of the $h->{LongReadLen} attribute is used to determine how much buffer space to allocate when fetching such fields. The $h->{LongTruncOk} attribute is used to determine how to behave if a fetched value can't fit into the buffer.

When trying to insert long or binary values, placeholders should be used since there are often limits on the maximum size of an INSERT statement and the quote method generally can't cope with binary data. See Placeholders and Bind Values.