Vugen error -27290

Hi,
I'm new to Vugen, i'm trying to access a weburl, and trying to fetch a table from the site.
I've written the following:
char *pmTable;
web_set_max_html_param_len("999999");
web_reg_save_param(pmTable,"LB=","ORD=ALL",LAST);
web_url("www.website.com", URL =.....);

I'm getting the following error:

Action.c(13): Error -27290: The "ParamName" argument (number 1) is NULL [MsgId: MERR-27290]
Action.c(13): Registering web_reg_save_param highest severity level was "ERROR" [MsgId: MMSG-26389]

What needs to be done here?
Any good set of documents for me to go through script recording in loadrunner/vugen??

Raghu