user registration and imploding code

Hi
I couldn't find the solution to this so here it goes:

Everytime someone registers at my site, he is able to register but with a lot of error code in my logs. They somehow point to usermodule problems.
Here it is:

2007-12-17 09:54 New user: Elisha e ... guest edit
error php 2007-12-17 09:54 You have an error in your SQL syntax; check the ... guest
error php 2007-12-17 09:54 implode() [ error php 2007-12-17 09:54 array_fill() [ error php 2007-12-17 09:54 array_keys() [ error php 2007-12-17 09:52 You have an error in your SQL syntax; check the ... guest
error php 2007-12-17 09:52 implode() [ error php 2007-12-17 09:52 array_fill() [ error php 2007-12-17 09:52 array_keys() [ error php 2007-12-17 09:50 You have an error in your SQL syntax; check the ... guest
error php 2007-12-17 09:50 implode() [ error php 2007-12-17 09:50 array_fill() [ error php 2007-12-17 09:50 array_keys() [

Then looking at just one of the errors in detail e.g. implode =

implode() [function.implode]: Bad arguments. in /home/mysite/public_html/modules/user/user.module on line 379

also =

array_fill() [function.array-fill]: Number of elements must be positive in /home/mysite/public_html/modules/user/user.module on line 379

and =

array_keys() [function.array-keys]: The first argument should be an array in /home/mysite/public_html/modules/user/user.module on line 378

what should i do?

btw, i am in cpanel shared account so can do no patches.