Subject Page xxx wrong type - Page 244141 wrong type (expected 5, found 1)

Hope my email isn't too long (and boring :-) )...

When trying to backup my database I receive the ffg. error.
"Page 244141 wrong type (expected 5, found 1)".

I am using IB 5.6 on NT(SP 6a, NTFS) on a dual processor machine (RAID
5). My database is approx. 5.6 gigs (8192 page size) split bet. 2
files :- the first file is 1.9 gigs, the second is 3.7 gigs. A third
file has been specified at page 732420 (though on the wrong path ie.
on c:\winnt\system32 instead d:\) but has been used yet (db hasn't
grown this big yet). The second file is specified to start at page

My questions are firstly what does this error mean (I understand page
type 5 means data file and page type 1 means header file). Does it
mean that a data page has overwritten my head page? I also know that
NT has a 4 gig limit but could it be that the database reach it limit
at 3.7 gigs (we only defined the 3rd file a few days ago)??

My second question (of course) is is there a way to fix the problem?

I've checked for different connection strings but all are the same. I
cannot backup database (with gbak) because of error. Am attempting to
gfix the error but unsure yet if thi will help.

Need help desperately. We do a tape backup every night but it appears
the last 2 night's backup have the same error.

Thank you kindly

PS. Have just noticed another error msg in IB log file "internal gds
software consistency check (Too many savepoints (287))" from 2 nights